CFX - Science topic

hello i have tried getting help on designing multi element airfoil, but was not successful. how to design the slat cove and flap cove geometry? how to mesh the multi element airfoil ? can you please suggest me a tutorial to follow. thanks in advance

Hello, community

I am looking for an optimization integration with CFX solver. For that, I want to know how to enable the parameterization option in CFX.

Your valuable answers are welcome. Thank you,

I want to compile 3 elements windkessel in CFX, I can use MATLAB and udf in fluent to realize this purpose, but I have no idea how to use windkessel model in CFX.

I would like to know if there are some codes or demo can help me

For simulating a time periodic flow, I increased simulation times up to 100s and use adaptive time steps.

But I didn't get desire result...I checked simulation setup several times...I don't know why CFX results are different from Analytical solution?

CFX simulation take about 20 days.

*may be by increase the simulation time get a better result!

what do you think?

I've done a qPCR reaction using Bio-Rad CFX Duet, 10 ul reaction, using EvaGreen dye.

as you can see, image 01 is what I think as a good amplification plot.

Today I do the qPCR again using a home-made qPCR master mix (also using Taq Polymerase produced in our lab).

Here is the recipe for it:

20 mM Tris.Cl pH 8.0

10 mM (NH4)2SO4

10 mM KCl

2 mM MgSO4

0.1% Triton X-100

200 uM dNTPs

1X EvaGreen

300 ng of Taq Polymerase (in 10% Glycerol, 25 mM Tris.Cl pH 8.0, and 500 mM Imidazole)

5% Glycerol

a week ago I using the same recipe for the assay, but it show great amplification plot

but today, it show amplification plot like image 04 (sorry i haven't moved the data yet so i just using Paint to show what the amplification plot looks like)

what can cause the weird shape of it?

Hello! We pump the contour of a metal tube with a diameter of 3 mm with oil with a viscosity of 0.0031 kg / m * s (abt. the viscosity is 4 times higher than that of water). We are interested in the pressure for pumping this circuit (at the inlet).

When validating the model in Ansys CFX with k-epsilon default settings, the difference between the result and the experiment reaches 100%, although the mesh is adjusted according to the tested and validated model, only on the water (with a maximum deviation of 10%). The Reynolds number in a pipe with a diameter of 3 mm is Re=2500, that is, we are dealing with a transitional flow regime, and the pipe is not hydraulically smooth in terms of the critical number Re=20d/"roughness".

Tell me, please, maybe for this mode it is necessary to use another turbulent model, for example, "Reynolds stress" or "k-epsilon" set up somehow differently? Maybe there are works in which a similar problem is solved, or there are works with recommendations on the use of turbulence models?

I am working on simulation of savonius hydrokinetic turbine in cfx. I have set inflation layer on turbine as shown in photos. It is observed in the previous investigation that, the non-dimensional wall distance (y+) must be less than 1 for the SST k-ω model for capturing the high levels of separation and adverse pressure gradients around the wall of the blades. Should i get Y+ value from cfx pre or cfx post as per my inflation layer ? Where i am getting the y+ value for turbine only in cfx? I have attached some figure of my setup.

I am doing an unsteady CFD simulation using CFX for a transonic axial flow compressor. The blade row model I am using is profile transformation, where I am getting two output files; .res and .trn (in a separate folder at each time step). I am trying to do post-processing in Tecplot, but I am not able to import the file into it. It would be a great help if someone let me know how to do it?

I'm working on ansys CFX. Has any of you encountered this problem and is there a solution? Because I can't work on old files that I completed and I can't make new files?

this is the error message

(( D:/new simulations/ new/ new model turbine does not exist and as such will not be be monitored))

I am working on wind interference effect in Ansys CFD. Even though the domain and geometry are symmetric, the results in the contour in CFX are not symmetric on Leeward side of the wind but the contour is symmetric in windward side of the building what could be the reason, what are the parameters should I check on?

I am studying thermal stratification effects on a pipeline using CFX (ANSYS) and then compute the thermal stresses using transient structural analysis. This is what I plan to do:

1) Apply an arbitrary force on the pipeline (IN STATIC STRUCTURAL)to compute stresses and continue reducing the element size till my solution becomes grid independent.

2) Compute results using CFX

3) Compute thermal stresses with structural analysis.

As I am involved with two different domains of ANSYS, do I need to carry out mesh independence for these two domains separately or just doing it in STATIC STRUCTURAL(point No. 1) will do the job for CFX as well?

Thanks.

Hi All

I used Bio-Rad CFX Manager version 2.1 for analysis of my qPCR data, but when was opening my data I see this message: version 06.10 is not supported. What does this message mean? Because this version does not exist.

Please guide me if anyone has information in this field.

Thanks

Hello, I am trying to run a simulation with real gas model from NIST using ch4a as working fluid. When I try to initialisate or run the simulation its not converging in Fluent,

in my simulation, inlet temp 110K, 0.02 kg/s ch4, pressure outlet 53 bar. just ıwant to see the phase change, ı try to understand the supercritical fluid, firstly ı tried to fit the curves at MATLAB, but there were wrongs with interpolations. ı reserach the rgp table from nist to CFX, ı couldnt, how do we deal with?

In Ansys CFX , if we define the expression of K and Epsilon. Than in epsilon profile, the turbulence integral length scale is required so How calculate the turbulence integral length scale in CFD simulation?

Hi

I'm currently using snappyhex mesh for meshing my fluid domain to run simulation in openfoam.

I found salome is better free alternative to snappyhexmesh, but the time required by the mesh created via salome is more than then mesh created using helyx (snappyhex).

There is a module callled meshgems in salome to be purchased in order to create hex mesh.

Is it worth buying meshgems to create hex mesh for openfoam application?

Hi. I am validating one Covid 19 kit and covering different labs. I mainly used Quant studio 5 & 7 and Biorad CFX 1000 touch( qPCR machines).

My kit validation has passed from many labs but from one lab I am getting too much Invalids(even after several reruns with some variations). However, procedure and conditions are same in all labs. How to resolve this?

Only thing remaining to retest that Staff used "White plate" but they run the program for the "Transprent plate ". Does it make the result invalid / No IC?

I am looking for to buy a RT-PCR machine-96 wells. Please mention your experience with the machine in your lab. Any pros and cons. Thanks

Hi everyone

Hope you are fine.

I tried to simulate multiphase species mass transfer in a bubble column reactor for a O3-water system with the Eulerian two phase model, VOF and mixture model in Ansys. Regardless of initial conditions, boundaries, discretizations schemes, mesh checking (min quality of 0.3) with sizes of 2 mm, 4mm and 2 cm, the case diverged after enabling species mass transfer, before enabling it I achieved convergence for the fluid flow equations at first stage of the simulation approach without any problem. I tried phase coupled and simple pressure velocity couplings with different Courant values (1,10 and 20) with adaptative timestep and also tried to decrease uder relaxation factors. I tried the 3 options available to model mas transfer in Fluent: Ranz Marshall, Hughmark and entering a constant value of global mass transfer coefficient; all cases diverged. I tried 3 inlet boundaries: mass flow inlet, velocity inlet and pressure inlet. For outlet I tried: deggassing, pressure outlet and outflow. The interfatial forces I considered where drag (grace) and lift (tomiyama). Turbulence models I tried all k epsilon and k omega families. I did 35 attempts with divergence, before I verified that values for Henry volatility were correct and other material properties. The system is a semi batch bubble column (11 cm diameter and 1.78 m of liquid height) with continuous circulation of gas (enters the domain at flow rate of 8.861 e^-5 kg/s). As you can see I have already tried everything in Fluent, that says to me that mass transfer models that Fluent offers do not addapt well to the default algorithm of calculation the software has, in fact if you read the theory guide it says Ranz Marshall, Hughmark models where formulated based on steady cases, multiphase flows are transient by nature. So I want advices or recommendations if you have experience with other software like Comsol, Open Foam, CFX for example, specially related to the learning process required to addapt to them, if the graphic interface is friendly user, etc. I am evaluating options so thanks in advance for any recommendations.

Walter Nolasco

For my recent work I need to know how to simulate waves using ansys CFX?

Any tutorials or simulations already done? I need examples and working models.

I am simulating a combustion chamber in Ansys CFX. The chamber has a refractory in order to retain the temperature inside the chamber. I have defined almost every essential phenomena and inputs in the CFX (Radiation, physical properties of refractory, and etc.).

I have two Domain in the CFX. First one is Fluid Domain and the second one is Solid Domain (which is the refractory). These two Domains have an interface which has been defined as well.

After solution, results show irrational wall temperature (outer side of refractory) of 1780 K which is so high!!!

I would highly appreciate if anyone guide me to find a solution for this problem.

after doing mesh i can't open CFX Setup.

could you help me to find solution.

Error message

Update failed for the Setup component in CFX. There is no previously saved CFX Setup to refresh or update. Please edit this cell first.

Hello,

I am a researcher at Aachen, Germany. I was facing some problems in my research to rerun my simulation in ANSYS 2021R2. I have a turbine which is heated with heat mats which have already simulated but due to unknown reasons, results are lost. So I was trying to rerun but I wasn't unable to enable all the heat mats to heat the turbine housing in the CFX. Can someone help me in solving this issue?

Thanks In Advance.

Nitin

Dear colleges,

I'm working a heat pipe simulation using the CFX code and I having some difficulty to model it. First of all, the device operates with 40% of volume fraction using water at a pressure of ~0.31bar (Saturation temperature ~25°C).

Initially I've divided the geometry (an annular space) in 2 parts: one representing the liquid and the other representing the gas. In the CFX-pré, I've created 2 domains (fluid-fluid).

In this point I have a question: for the gas, it is necessary to consider a mixture of water steam and air or only the steam? Second In CFX I've not find a way to set that in one domain I have boiling of liquid water while in the other domain I have condensation occurring at the same time. Is it possible? My question is motivated due to in CFX I can define that a fluid in continuous, dispersed and so on. But I can't define that its morphology is different in the other domain (for example: while the liquid water is continuous in one domain, it is a dispersed phase (droplets) in the other. The same is valid for the steam (or the air-steam mixture): it is a dispersed phase in one domain and a continuous fluid in the other (where condensations takes place)).

The heat pipe have no adiabatic section, but only the evaporator (where the liquid initially relays) and condenser (in which initially there is an evacuated space with some air or steam - as mentioned, I have no idea if its necessary to consider both or only the steam because I've tried both approaches a not one have resulted in a converged simulation).

I would be wonderful if some one could could give a clue of which way I should follow.

Thanks in advance.

I try to create a protocol for thermal shift assay using Bio-rad CFX manager.

However, CFX96 and software are new to me and I am not able to create the protocol to follow the methods in the many publication. 

First I tried to set up the temperature as gradient, but it only take one measurement after temperature reach to the max. Next, I set each temperature (25 oc to 90 oc, 0.5 degree increment) with adding a measurement and holding time fore 30 sec. However, there are maximum steps i can set this (up to 99 or 100 steps). Also, I cannot set up the heating rate with this way. 

I am wondering if there is an another way to set up the protocol or there is a template protocol i can modify..

The pipe is not oriented with respect to any axis.

I have a master mix one step RT-qPCR with ROX (and another with low ROX), with ROX being a reference dye. However, the RT-PCR instrument of my lab is Bio-Rad CFX Connect and the software used is CFX Maestro, for which I do not have any option/setting to select "ROX" as "passive reference".

Can I use this mastermix independently of this fact?

Will this fact have any implications in the PCR reactions?

Do I need to sacrifice the data collection in one of the channels to normalize to a passive reference?

or as option: Can I use a reaction only with my master mix with primers, without probe, in order to subtract the signal given by this reaction to the others reaction in which I have my probe? If yes, how can I do that "subtraction" in the CFX maestro?

Hello,

I am currently working on an axial pump. The original geometry didn't perform as well as I expected, so I plan to improve its performance. But all the ANSYS tools I tried either didn't work or didn't give me control over the variables I wanted, so I decided to use C code.

Is there any way to link the C code to Ansys CFX?

Thank you very much.

Hello everyone,

Hope all is well with you.

The goal is to simulate a hollow ventilated wall (Air or water could travel through the wall - interior and exterior) for its energy performance, but I need to know what options I have. I can indeed use CFX to do such simulations, but I would like to know if there is a simpler and more recent program that I can use.

I greatly appreciate your suggestions.

Best,

Mohammad

Hello, I went through the Fluent Theory Guide and other Ansys learning resources, however I couldn't find the answers to the following issues.

Let's discuss the problem on the example of a general steady RANS k-omega case.

No slip Wall

U is set to zero, k is set to zero, omega is given by a specific equation.

1. What about pressure? Does Fluent use the zeroGradient condition for pressure on a wall? It's done by default in OpenFOAM.

2. NS momentum equations are 2nd order in space, so the boundary conditions should involve the normal derivative (e.g. dUn/dn=0), if I am not mistaken ?

3. Consequently, the turbulence transport equations are 2nd order in space as well, so should their respective derivatives be specified on a wall?

Velocity Inlet

U, k and omega are specified.

4. What about pressure? zeroGradient?

5. Refering to question 2,3 - should a Neumann BC be specified for U, k, omega?

Pressure outlet

Fluent Theory guide says that all variables (apart from pressure) are extrapolated from the interior. However, that does not sound right. Imagine a highly diffusive system, wherein turbulence (or any other scalar) is diffused upstream, faster than the downstream convection. In such a case, turbulence properties at the outlet would affect the solution in the domain.

6. As a consequence, what BC are imposed for U, k, omega? Mentzer suggests "intervals" which freestream turbulence properties should be taken from. https://turbmodels.larc.nasa.gov/sst.html

Symmetry

Fluent specifies zero convective/diffusive flux across the symmetry plane.

7. We should specify a value of k and omega at the symmetry anyway... right? It has to be done in OpenFOAM...

Thank you very much for your time and effort, feel free to make a comment on that.

I need to measure the water depth in the cylinder ( the picture attach) that mixes with air in Ansys CFX, and I don't find an excellent expression to do that.

Hi,

I am trying to simulate reservoir performance. While COMSOL allows true 1D and 2D problem definitions, does CFX lack because it is 3D dominated?

*Note:

I would like your opinion from a reservoir simulation perspective where we usually encounter greater aspect ratios between well and reservoir dimensions.

Hi friends, I'm currently working on some 1-way FSI problem using ANSYS Workbench. I'm trying to calculate the transient temperature field of a shell structure in CFX (60s in total in 240 time steps, which is 0.25s per time step), and transfer the temp field results to Transient Structural module, so that I can calculate the transient thermal stress distribution of the shell structure.

The problem is: when I'm trying to transfer the all the temperature results (240 steps in total) into Transient Structural, all I get is the last (the 240th) temperature field, as is shown in the attached figure.

Is there any approaches to transferring my results of every step into Transient Structural rather than only the last one?

I am simulating an air screw compressor in CFX using the immersed solid method. I am able to run a simulation, but the results are confusing. The total pressure is not increasing even as work is done on the system. The inlet condition is a mass flow rate, and the outlet condition is 7 bar. I cannot find any posts about this problem and am not sure what is wrong with my setup. If you need any more pictures or information, please let me know.

I'm looking for standard axial compressor blade row data files for CFX simulation , so could somebody tell me where can I find them ?

Like rotor37 , PBS rotor , and something else about them .

IGES , data , geomturbo , xt formats can be fine.

I will be very grateful if someone tell me where to find them or give me these files . Thank you .

I'm trying to model a combined sinusoidally pitching and plunging oscillating hydrofoil, with just the pitching as a mesh movement, while adding a velocity source term to the fluid in the opposite direction of the plunging motion to mimic the effect of plunging. The units of a general momentum source term in CFX are kg m^-2 s^-2, dimensionally equivalent to density * acceleration, so I created an expression to calculate the foil acceleration and used it to create a momentum source term with those dimensions. Using the term in a transient simulation however produces velocity fields in the fluid domain that don't make any sense, and certainly aren't consistent with the plunging motion expected. Are there any ways to formulate a general momentum source term so that it results in the addition of a purely velocity component to the fluid?

I have been consistently getting very high RFU values at the beginning of most of my qPCR runs. The RFU then drops off over the first 10-15 cycles and then increases as the thing I am amplifying amplifies (See attached image). I'm using a BioRad CFX 96 with PowerUp Sybr Green Super Mix by Thermo. Any idea what is going on here?

Hello everybody, I would like to simulate a three phase reactor and study its hydrodynamics. I would like to know which type of software is better? I have a good command of ANSYS Fluent and I am really convenient with it but i have no experience of working with OPEN FOAM or CFX ...

Do you recommend to use another one? please let me know your opinion.

Thanks

I am working on a CFX 96 machine to determine reaction efficiency of my gene of interest.

After performing a serial dilution of my cDNA template, I was able to find great reaction efficiencies for 3/4 genes (102.5%).

One gene seemed to have odd results and when I reperformed the serial dilution I again found a similar pattern on the standard curve.

Sample PER B x10: 6 1:10 serial dilutions

Sample PER B x5: : 6 1:5 dilutions

Reaction:

10uL SyBER Supermix

7uL NF Water

1uL of each forward and reverse primer 5uM (primer concentration tested during a gradient with good product)

1uL of Stock cDNA produced from Trizol RNA extraction of animal brain 255ng/uL diluted as stated above

I have run NRTs with this sample and can rule out gDNA contamination

I have attached two screenshots of my standard curves

Is there any explanation for why I am getting such odd Cqs (~26) even after 6 serial dilutions?

If there is any more information I can provide please let me know

I would appreciate any comments on the following problem. I need to calculate mean fields (e.g. pressure, velocity and vorticity), for which I activate Trn Stats tab in CFX-Pre. However, what I get is not as expected; the calculated Trnavg variables differ from one time step to another, as opposed to being independent of simulation time. I'm really confused about what these Trnavg (Arithmetic average) variables actually represent and how the solver calculates them.

Hi,

I am trying to simulate a centrifugal compressor using the Ansys CFX.

However, the outlet pressure shows large oscillations even at the rated flow. The same simulations using the Fluent shows a constant pressure at the outlet without any oscillations.

Can anyone help me with the solver/turbulence model/.. settings that have to be used in Ansys CFX?

Thanks in advance

I am modelling a simple pipe flow of a non-newtonian fluid (Ansys CFX). I'm aware that this is an area of developing knowledge.

The viscosity model for the non-newtonian fluid is the Carreau-Yasuda model. The fluid properties are taken from literature (Escudier et al, 2005). I thought it would be interesting to plot the variation of viscosity with shear strain rate in CFX, and compare that to the original viscosity relationship.

The attached image shows this plot. Grey line: Original data (Escudier et al 2005). Yellow line: Original data plotted using CFX slightly modified Carreau-Yasuda equation (I need to look into this separately). Blue line: Laminar flow, approx Re=780. Orange line: Turbulent flow, approx Re= 45000. (N.B. picked these Reynolds numbers for a comparison, they're not arbitrary).

The question is: Why do the CFD results for shear strain rate vs. dynamic (apparent) viscosity deviate so far from the input relationship?

My thoughts are that this is a mathematical issue in the CFX solver. I'm having difficulty pinpointing an explanation though, my knowledge in this area is still developing.

For reference, I'm a Masters student in Mechanical Engineering.

What should be my valid boundary conditions if i know only exit Reynolds number (exit velocity is known) ?

The Mach number is below 0.2 so the fluid is incompressible.

Thanks

Hello.

I am working on a project which we need to calculate bubble size of CO2 injected into water.

I need some help with simulation in Fluent or CFX or any other program.

I ran 96 well plate with temperature gradient 55-65 and a melt curve. It took unreasonably long to run melt curve, after two hours of running melt curve I stopped it from CFX manager software, which did not show any response. Finally I had to power off the cycler. After restarting both computer and the cycler, the run gets stuck at initializing step ('starting run'). If anybody has such experience please share your solution/suggestion?

Hello,

this question is not as trivial as it may seem.

The Laminar model in Fluent/CFX is pretty stable even when the physics are not laminar at all (internal flow, Re=20k, bifurcations/pipe bends that turbulise the flow even further...)

If it were a simple direct solver, undamped turbulence (combined with a typical RANS grid and a large timestep) should cause divergence, as it is the case with icoFoam.

If you know what the "Laminar" model is based on or you have any references, please let me know.

How can I modify the production term with a different expression of TKE transport equation in CFX?

I learned about I may use CEL function. But could someone kindly tell me more details about the code and settings in CFX-Pre?

Thank you.

So the lab that I work in generates a lot of AAVs and we titer them via QPCR. However, I've been noticing that the entire time, the efficiency has always been very low (anywhere from 40-80%) with certain primers. It's apparently been that way since before I started and before the person who trained me started so I'm trying to troubleshoot this.

We typically use WPRE as the element we titer with. My PI has always said that those primers are the most reliable in his experience and we've generally kept to that except in cases where the viral genome does not contain WPRE.

I've tried everything I can think of from linearizing the plasmid DNA for standards, running gradients to be sure that the annealing temperature is correct, changing the annealing/extension time from 30 seconds to 1 minute, and played with primer concentration a tiny bit. I'm beginning to believe that there is some sort of secondary structure in the amplicon that is causing this poor efficiency or the machine (Bio-Rad CFX Connect) needs to be calibrated. I use Bio-Rad's iQ SYBR Green Supermix.

My protocol generally has a 3 minute 95C initial activation, 10 second 95C denaturation, and a 30 second 55C annealing/extenstion time with 40 cycles. I've done melt curves and am getting specific products which is good, but the efficiency is low no matter what I'm changing or doing. My r^2 values are also generally good (between 0.98-0.99) and my replicates for my samples are also typically close in Cq value. I just can't seem to get the standards right for some reason. I use a 1:3 dilution and have considered altering that to a 1:5 to see if that improves things but I don't really see why that would make a difference.

Does anybody have any ideas, tips, or tricks that can help me troubleshoot this protocol?

I'm working on a project for the simulation of flow over bluff body and I want to find the CP values distribution along the bluff body. I have no idea on how to enter the formulae in the CFX simulation software. Are there any manual for formulae that is used in ANSYS CFX.

Purchased kit to run on old iCycler but directions did not have a method. Only said to use CFX

Manager Software and select the appropriate thermo-protocol for the detection or quantification of Legionella. Looking for details about this protocol.

Hi there,

Some research showed me I am able to import datasheet from Excel to Ansys through a 'profile', but gravity requires a 'parameter' input. Is there anybody out there whom is experienced in writing gravity vs time parameters?

Some more background info: I am currently performing research for my thesis on fuel slosh behaviour inside a small fuel collector with an approximate volume of 8L. The design will have two high pressure fuel pumps 'inside' the collector, whereas the inlet of the pump requires to remain wet throughout the race. My case describes either a baffle optimisation or to just visualise the minimum remain fuel level is feasible (for example 200mL) before the pumps will be exposed to air surge.

The software I am using to simulate the fuel slosh behaviour is CFD Ansys Fluent. I am able to generate the internal domain, mesh it accordingly, do a fuel filling test (through inlet mass flow and pressure outlet), but I am unable to define a variable gravity, which represent the G-forces.

G-force on the race car is measured with a 25Hz sensor, which results with a new G-force every 0.04 seconds. The data is quite rough, so I am not able to extrapolate it in to an equation. Multiplying the local G-force with a factor of 9.81 will result in the local G-force, assuming the basic y-direction will always have -9.81.

CFX is able to handle variable gravity through expressions, but is Fluent also able to do it in some way?

Cheers, Sander

| Vertex Based Partitioning |

+--------------------------------------------------------------------+

Partitioning of domain: Default Domain

+--------------------------------------------------------------------+

| ERROR #001100279 has occurred in subroutine ErrAction. |

| Message: |

| SYMASS_ZONE_EL : The solver ran out of temporary space while buil- |

| ding a linked list for a domain. Try setting the expert paramete- |

| r "topology estimate factor" to a value greater than 1.0. Values |

| higher than 1.2 should not be necessary. |

| |

| |

+--------------------------------------------------------------------+

+--------------------------------------------------------------------+

| ERROR #001100279 has occurred in subroutine ErrAction. |

| Message: |

| Stopped in routine SYMASS_ERROR |

| |

| |

| |

| |

| |

+--------------------------------------------------------------------+

+--------------------------------------------------------------------+

| An error has occurred in cfx5solve: |

| |

| The ANSYS CFX partitioner exited with return code 1. |

+--------------------------------------------------------------------+

+--------------------------------------------------------------------+

| The following user files have been saved in the directory |

| C:/Users/Shahmohammadi/Desktop/New folder (2)/New |

| folder/mesh/1010_pending/dp0_CFX_Solution/Fluid Flow CFX_001: |

| |

| trace |

+--------------------------------------------------------------------+

+--------------------------------------------------------------------+

| For CFX runs launched from Workbench, the final locations of |

| directories and files generated may differ from those shown. |

+--------------------------------------------------------------------+

This run of the ANSYS CFX Solver has finished.

How to calculate the hydrodynamic forces with CFX ANSYS?

I need some tutorials or examples for hydrodynamic forces for offshore structures.

I am currently running absolute quantification PCR on DNA samples and I use the 3-step cycling steps recommended by the manufacturer (Bioline). Their thermocyclic conditions does not suit me, including the melt curve analysis. I am still optimising for 2 weeks now (sighs!!)

Can anyone share his or her protocol with me.

Thank you

I'm currently working on a project that is using the SST k-w turbulence model. This model, reads velocity flow on the near wall region of a bluff body as well as the far wall region which is the combination of k-w and k-e turbulence model. The SST k-w model can be the best approach in solving this type of flow problem. The only issue is defining this model onto the CFX pre process.

What is better using CFD or CFX to simulate axial flow pumps using Fluent and why?

I have a problem with Ansys CFX. My runs aren't converging. I have attached a screenshot of a previous run.

Any ideas on how to resolve this?

Hello,

I'm beginner about CFD and I'm modeling coal combustion in CFX but i have this error :

"CFX-Pre Application Error

Application Error in CFX-Pre: ERROR

CCL validation failed with message:

Error: At least one sub-object of type 'MATERIALS LIST REDUCTION' is required in /CFX RIF:CFX RIF 1

Error: At least one sub-object of type 'SCALAR DISSIPATION RATE' is required in /CFX RIF:CFX RIF 1

Error: At least one sub-object of type 'OXIDISER COMPOSITION' is required in /CFX RIF:CFX RIF 1

Error: At least one sub-object of type 'MIXTURE FRACTION' is required in /CFX RIF:CFX RIF 1

Error: At least one sub-object of type 'PRESSURE AND TEMPERATURE' is required in /CFX RIF:CFX RIF 1

Error: At least one sub-object of type 'FUEL COMPOSITION' is required in /CFX RIF:CFX RIF 1

Error: At least one sub-object of type 'LEWIS NUMBERS' is required in /CFX RIF:CFX RIF 1

Error: At least one sub-object of type 'MIXTURE FRACTION VARIANCE' is required in /CFX RIF:CFX RIF 1"

Please, help.

I have created stator blades and rotor blades by using coordinates and used SolidWorks. However, I tried to create fluid volumes for those blades, to simulate in CFX and have not achieved yet. I need to generate the following kind of Fluid volume. I have tried Bladegen. But it doesn't facilitate blade creating from given coordinates. Hence, the fluid volume couldn't generate through it.

Could you please give me some insights on this?

I simulate a wave maker in CFX with VOF model.The results are Validated with some paper results.but I need to plot path of some particle of water.I search the web and forums but I didn't find any thing.At last I found that in VOF model can't plot particles path.

What is your answer to my Question?

"How I can plot path of some particle of water with VOF Model in CFX?"

Hello,

I have an inlet profile data obtained from my previous work in *.csv format. I have initialized it via the "Initialize profile data" setup, but I unable to use it for an Inlet BC for my current simulation.

Any ideas will be greatly appreciated.

Best Regards

Hi everyone, I really need your help.

Currently I'm doing RNA extraction with column-base methods and qRT-PCR (with Biorad CFX 96 Deep Well Real-time System) SARS-COV2 detection on human swab samples.

In the first two weeks I've use an amplification kit which primers were targetting Sars-Cov 2 gene E, with FAM and VIC as fluorophores and I had perfect curves and beautiful results. Than this kit was sold out on the market (just like everything right now) so I had to replace it for an amplification kit which primers are targetting Sars-Cov 2 gene N and with FAM and Cy5 as fluorophores and than the problems begin. All the components needed to do the master mix came in this kit (oligos, taq, RNA internal control, etc...).The thermocicler was programed according with the manufacter and with the help of a biorad technician. Most of what I've got it's on the files attached. When I rerun this samples with a 1:5 dilution I get a normal curve and a negative results.

Do you have any theories of what could be happening?

Thanks in advance for your help!!

Hello everyone.

I am looking into near-stall behaviour of the multistage axial compressor using CFD with RANS method.

Kind regards,

Dr A. Szymanski

Hi,

I want to write gradient expression according to following attached figure. But I don't see such as this term in CFX post.

The governing equations used for the simulations were continuity, momentum and .

I am grateful that guide me about this case.

Thanks.

How can one become an expert in CFD?

Please help others showing here tutorials for experienced CFX and Fluent users.

transient sliding mesh method used for the simulation of two-phase liquid-solid in stirred tank reactor. in cfx manual mentioned that first use the frozen rotor for better convergence behavior then turn to the stage for better result. recently I noticed that particles can't pass through one of the frozen rotor or stage interfaces. is it true? if yes, which interface model, frozen rotor or stage?

Understanding the results from a open air channel simulation: The output shows very different results when using [Inlet, Outlet,...] Opening vs Entrainment BC. No steady one-direction forced air [fan, pump...] is used, so inlet/outlet BC can't be used and the available air stream(s) is/are turbulent.

- It seems that opening BC has one-directional flow in contrast with all-direction flow entrainment BC?

- If correct, does it explain the huge discrepancies between the inlet(s), outlets(s) flow rates... output results?

Requested information: What should be used as boundary condition (inlet, outlet, etc...) in this condition?

Thanks

Hello all.

I am simulating a centrifugal pump. Before I started simulating, I ran few test cases on a simple setup to look into the y+. In the test case (which is a simple pipe flow), I could see that the yplus value specified for inflation matches the post-processing results. I am using SST turbulence model with automatic wall treatment.

When I am taking the same yplus to pump, which consists of rotating flows, the yplus fails. Now, as I did the sensitivity analysis using (10-15 layers in the boundary layer), y+ <1 and yplus 20-200 (where SST behaves like k-epsilon),l. However, I could not find the yplus specified for inflation to be matching with that of the post processing results. The difference is atleast an order near the blade walls. Now, I assume that it might be due to the large separation zone in the pressure side. Besides, the effect of y+ variation is not significant to compute the performance for the pumps.

My question is: Has any researcher found yplus value to be fully satisfied in case of turbomachines in CFX? Is it important to verify yplus (for Journal Papers) value even when we know that the wall function is not affecting our parameters of study?