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# Computational Fluid Mechanics - Science topic

Explore the latest questions and answers in Computational Fluid Mechanics, and find Computational Fluid Mechanics experts.

Questions related to Computational Fluid Mechanics

I am running sloshing simulation in a rectangular tank using ANSYS fluent. reynold's number lie in turbulence and as it is a wall bounded problem I calculated the first cell height of inflation layer assuming y+ value=50.(turbulence range is 30 to 200). but, some literatures stated that having y+ value=1 (laminar) resulted in better accuracy. so, how should I assume my y+ value?

Dear,

I am trying to use Salome recently, first with a simple geometry, as attached.

But after I used the partition tool, there are some internal faces, which are not expected at all, as highlighted in the attachment.

Could any body show me how to remove the internal faces please?

Thank you in advance.

Yours Sincerely,

Bill

- What is the best software (open or closed source) for solving in thermofluids problems among (Comsol, Ansys fluent, open foame, SimScale, Simcenter, mathlab, pyhton, R, Wolfram mathematica.......etc). Which ones can be used togther (exp: i use comsol what is the second one which could be more usefull) ?

I have a specific case about internal pipe flow with constant heat flux. Although the inlet boundary condition is laminar, the flow is a passing transition (a significant part of the tube) and turbulent regime along the tube (because of the change of thermophysical properties depending on implied heat). SST models with intermittency term (For fully laminar flow, γ = 0 and the model reverts to a laminar solver. When γ = 1, the flow is fully turbulent.) can catch laminar/transitional and turbulent flow regimes. These models were designed for turbulent inlet boundary conditions (models solve intermittency term, so it needs extra boundary conditions such as turbulent intensity). Can Transitional SST Models be used for laminar inlet / turbulent outlet boundary conditions? If so, what is the approach?

Regards,

EB

Hello dear Researchers :

Does anyone have modeled, or have literature on how to mathematically model a :

Fluid Flow of a :

- Non-Newtonian Fluid

- Non-Isotermal Flow

- Compressible Flow

- Polymer.

Thank you for any help, I'll appreciate it !

Best Regards !:)

I'm simulating a 3D wing with winglet (on the tip) using ANSYS Fluent. I'm confused about how to calculate the area in reference values section. Please check the attached pictures of my wing model.

I guess my question is quite simple: you know how for compressible CFD codes we have the Sod Shock tube problem that we can use as a benchmark. What if I now want to expand my code and add chemical reactions to it, what would be a good/similar test problem that I could use to validate how well my code runs?

This Discussion is to help people that are both experts and newbies in the field of CFD and simulation to help each other and to give links to websites and drop materials that are invaluable to push us to the frontiers.

Hello Everyone,
I am trying to simulate a Y shaped channel using VOF method in Ansys Fluent. Discretization of the model has been done. Inlet velocities of both dispersed and continuous phase are calculated using Capillary Numbers. I have considered no slip boundary condition at domain wall. Hereunder is the method I have applied while performing the simulation:
Method-
a)pressure velocity coupling scheme= coupled with vof
b) Discretization method- Green gauss cell discretization method
c) Pressure-PRESTO
d)Momentum-Second order upwind
e) Volume fraction-compressive
f) Transient formulation-Bounded second order implicit
Provided a suitable Residual of 10^-6, Time step size- 100 and Max iterations/step size-20.
My objective is to form a Janus Droplet. But droplet is forming but no janus droplet formation took place applying this methodology. Can anyone please throw a light on where I am doing wrong or is there any other process to form a Janus droplet.

I would like to study the apo form (lipid-free) of a protein that only has been crystallized with lipids. I want to explore if it is possible to generate with a molecular dynamic a reasonable structure, making subtraction of lipids in several steps until obtaining the apo form. Likewise, I don't know if, during the molecular dynamic trajectory, it is possible to disappear lipids. I am thinking of using programs like GROMACS, AMBER, etc.

In an article, the authors obtained the Nusselt number like 6.487. When I apply the same operating conditions for the same geometric model, I obtained the Nusselt number like 3.741. How can ı found the nearest value to authors? Thanks for your interest.

Note: I use the (h*Dh/k) for Nusselt number calculation. For the calculation, I obtained surface heat transfer coefficient from Fluent in Excel and I took the average values at thermally developed region for heat transfer coefficient values. In article, thermally developed region was used for calculations.

I just want to find out a good book on fluid flow through channel which is having mathematical modelling of fluid flow through different type of channels eg vertical channel, inclined channel, wavy channel etc.

Hello Everyone ,

I am simulating a 3D airfoil in fluent . The results I am getting for lift coefficient are within 5% error limit of the experimental values .

However , the results for drag coefficient are significantly lower than the experimental results .

I have read in literature that this under-prediction of drag coefficient is due to the lift induced drag in experimental results and that CFD does not account for lift induced drag . Is it true ?

For the 2D NS equation of the stream-vorticity formula:

^{$\partial w/ \partial = J(\psi,w) + (1/Re)\Delta w+f(x,y,t); w = -\Delta \psi$.}

^{Using the Fourier-Fourier basis Exp(I(k1*x+k2*y)), I got the evolution in spectral space:}

^{$dW/dt = LW+N(W,\psi_hat)$,}

^{where W, \psi_hat are complex. It has the solution W(t;W0) if the initial values W0 is given.}

^{To search the periodic orbits of this problem with a period T, I tried to solve the equation }

^{$ F(W0,T) := W(T;W0)-W0=0$,}

^{Using the Newton search, I can get:}

^{$ \partial W/\partial W0 * dW0 + \partial W/\partial T *dT = -F(W0,T)$. (*)}

^{Now the problem I meet is: both dW0 and dT are complex since the coefficient matrix of (*) is complex.}

^{SO how can I get a REAL dT?}

^{THANK YOU VERY MUCH!}

Dear all Professors & fellows,

Respected to you all.

Thank u for looking this question and adding your valuable comments or understandings to this question.

I saw few published manuscripts & found that, authors have evaluated TAWSS & OSI for rigid case of CFD simulations.

My question is that, actual meaning of TAWSS is - Avgd WSS over one cardiac cycle, which is used to determine the shear stress magnitude applied on

**vascular wall surfaces**during one cardiac cycle.So, how & for what reasons TAWSS & OSI parameters were calculated when they have done CFD simulations where they don't have vascular wall surfaces or absence of wall.

As of my understanding I believe that, these parameters can be only evaluate if you are doing FSI simulations (fluid structure interaction studies) but not for CFD (Rigid wall) cases because that give incorrect results as CFD cases doesn't have surfaces or walls.

SO, can you please tell me how much I am correct here .

I am saying that, TAWSS, OSI should be evaluated for Fluid structure interaction cases only but not give correct results for CFD (rigid wall cases) so not necessary to calculate in rigid cases of artery.

is that I am correct??

Please clarify me by your valuable comments or reply me.

Thanking you in anticipation,

Regards,

Dear all;

I am trying to simulate non-Newtonian fluid flow in porous media with the help of Palabos software. Palabos is a C+++ open-source library that solves flow problems with the lattice Boltzmann method. I am not familiar with object-oriented programming and I want to extract a value from a template that is used in every iteration. To be more precise; I want to print Omega (which is an (Nx-1)*(Ny-1) dimensional matrix) in every 250 iterations in the form of gif or data to validate my result. I added pcout to print variable in this function and it works but it is repeated every iteration which generates too much data ( imagine 200*200 lattice and 10000 iterations!).

I will be really glad if you could help me through this. the code is provided below. also, I uploaded

.h and .hh file to this message

Many thanks;

Elahe;

template<typename T, template<typename U> class Descriptor,int N>

T CarreauDynamics<T,Descriptor,N>::

getOmegaFromPiAndRhoBar(Array<T,SymmetricTensor<T,Descriptor>::n> const& PiNeq, T rhoBar) const

{

T nu0_nuInfoverCs2 = (global::CarreauParameters().getNu0()-global::CarreauParameters().getNuInf())*Descriptor<T>::invCs2;

T nuInfoverCs2 = global::CarreauParameters().getNuInf()*Descriptor<T>::invCs2;

T nMinusOneOverTwo = (global::CarreauParameters().getExponent() - (T)1)/(T)2;

T lambdaOverCs2sqr = global::CarreauParameters().getLambda()*Descriptor<T>::invCs2;

lambdaOverCs2sqr *= lambdaOverCs2sqr;

T piNeqNormSqr = SymmetricTensor<T,Descriptor>::tensorNormSqr(PiNeq);

T alpha = lambdaOverCs2sqr * piNeqNormSqr *(T)0.5

*Descriptor<T>::invRho(rhoBar)*Descriptor<T>::invRho(rhoBar);

T omega = carreauDynamicsTemplates<T,N>::fromPiAndRhoToOmega(alpha, nu0_nuInfoverCs2, nuInfoverCs2, nMinusOneOverTwo, this->getOmega());

T tau=(T)1/ omega;

T visco=((T)2 * tau - (T)1)/(T)6;

pcout << "" << visco << std::endl;

return omega;

}

**Discussion of the state of art on the application of the Ertel's potential vorticity theorem in atmospheric physics & physical oceanography.**Prof. H. Ertel generalized Rossby's work proposal of 1939. Prof. Rossby firstly proposed that instead of the full three-dimensional vorticity vector, the local vertical component of the absolute vorticity is the most important component for large-scale atmospheric flow.

Via an independent paper published in 1942, Prof. Ertel identifying a conserved quantity following the motion of an air parcel proved that a

**certain quantity called the Ertel potential vorticity is also conserved for an idealized continuous fluid.**Several links to check on the topic powered by ResearchGate:

What are the advantages of Finite volume method (FVM) over Finite difference Method (FDM) for particularly flow simulation (CFD) ?

Hi

I'm trying to simulate thermosyphon. But when the UDF read, and I want to run, the following error was printed!

please help

Dear all,

In my simualtion domain, I need to use mixture of gas ( N2 gas with 20% CO2) at INLET in ANSYS Fluent.

Mixture model, and species model, may be these models work. Actually,

**I need your support to notify the model and how to put the above specifications on that model too.**Regards

I have a case, which is about internal flow with constant heat flux. Although the inlet boundary condition is laminar, the flow is passing transition and turbulent regime along the tube. As known, the intermittency term is 1 (so, admitted as turbulent inlet BC) for freestream velocity for external flow, I would like to learn that whether using the transitional SST model by laminar inlet boundary condition in the pipe is the corrects way or not.

Best regards,

I am trying to simulate a heterogeneous reaction between two phases in Eulerian multiphase model. I have written a UDF and it compiles and runs well. The reaction is: C+2H2--> CH4. Although my solution shows reasonable values for reactions rates, but I do not see any changes in Hydrogen concentration from the inlet gas. Can anyone where the problem is arising from?

I need the following tutorial zip files to learn the basics of the software:

- Using sliding and dynamic meshes
- Modeling solidification
- Using the Eulerian Granular Multiphase Model with heat transfer
- Postprocessing
- Using the Adjoint Solver – 2D Laminar Flow Past a Cylinder
- Simulating a Single Battery Cell Using the MSMD Battery Model
- Simulating a 1P3S Battery Pack Using the MSMD Battery Model

- How to find a relationship between velocity and weir landing length (X') as shown in figure?

Hello all,

I am looking for an method / algorithm/ or logic which can help to figure out numerically whether the function is differentiable at a given point.

To give a more clear perspective, let's say while solving a fluid flow problem using CFD, I obtain some scalar field along some line with graph similar to y = |x|, ( assume x axis to be the line along which scalar field is drawn and origin is grid point, say P)

So I know that at grid point P, the function is not differentiable. But how can I check it using numeric. I thought of using directional derivative but couldn't get along which direction to compare ( the line given in example is just for explaining).

Ideally when surrounded by 8 grid points , i may be differentiable along certain direction and may not be along other. Any suggestions?

Thanks

Dear all,

I'm doing a two way FSI problem with Static Thermal and Fluent as my systems. Something like the video attached. While solving the system coupling threw the following error: "Update failed for the Solution component in System Coupling. The coupled update for System, Fluid Flow (Fluent), threw an exception."

In total there were four errors. See the image attached.

Anyone with any suggestions or advice is appreciated.

Regards,

Nikhilesh

If POD or DMD is applied to flows which are not turbulent in a broad sense, which means that there is not much chaotic mixing, will they carry any significance? Because there will be not many spatial and temporal scales like in a turbulent flow.

An aircraft is consist of many sub-parts , while estimating the Reynolds number and y+ value first layer height which length do we consider as the characteristic length to be used in the respective formulas ?

I am solving a transinet convection-diffusion equation

u_t + a*u_x - nu*u_xx = 0 in (0,1)

Taking,

Convection coefficient a = 1

Diffusion coefficient nu = 0.005

Number of elements = 100

I got Peclet number Pe = 1

For same case now,

Time step = 0.01

End time = 0.6

I got Courant number C = 1

I need following 4 conditions to fulfill.

1). C =1 and Pe = 5

2). C =1 and Pe = 100

3). C =3 and Pe = 5

4). C =3 and Pe = 100

My question is:

What should be the value of

"Convection coefficient a",

"Number of elements",

"Diffusion coefficient nu",

"Time step" and

"End time"

to get these 4 results separately.

Dear all:

I need help, I hope there is someone out there who can help me.

I finish drawing the 2D geometry of an Air Solar Collector with an undulated absorber plate (in contrast with a flat plate absorber). This is a ~~~~~ shape plate to capture the sun radiation.

So I already added the materials and (try to) add the Physics to my model:

- Single Phase FLuid Flow - Laminar Flow

- Heat Transfer in Solids

- Heat Transfer in Fluids

But when I run the simulation, even though I have the Heat Transfer in Solids and the Heat Transfer in Fluids modules included in my model, the Results doesn't show whatsoever the Graphs for the Temperature Distribution, or contrours. Also the Pressure Results Graph doesn't shows anything

I'am attaching two images: on of my model's geometry, and one with the solution of the Velocities distribution, but this is as much as I can arrive to.

I'm sure I am doing something wrong with the Boundary Conditions I'm entering.

These are all

**the Boundary Conditions**I'm trying to use**:****i.**

**Constant Radiation Heat Flux**at the top of the glass cover.

**ii.**

**Constant Convection Heat Flux as Losses**from the top of the glass cover to the ambient.

**iii.**

**Tried**to establish a

**Constant Conduction Heat Flux**from the bottom of the collector to the surroundings (to represent

**the Heat Conduction Losses**from the bottom of the Collector to the roof and environment).

**iv.**

**Isothermal Walls**at both of the sides of the air cavity.

**v.**The

**No-slip Boundary Condition**(u=v=0) at the inside of all the walls of the air cavity.

**vi.**An

**entering Air Mass Flow**from the left to the right of the bottom air cavity.

**vii.**I wanted to establish also and

**exiting Mass Flow**at the right side of the bottom cavity, but couldn't. So instead, I established this Condition as a

**Pressure at the Outlet**, as the Boundary Condition.

So I'm pretty sure I am doing something wrong with one or several of the BC.

I hope someon can give me some help me. I'll appreciate it

Thank You !

Hi everyone ,

I am implementing Acoustic model in FLUENT. Geometry is 2D. By using FW-H model, I am facing difficultly to understand these things. ( I have already read FLUENT manuals and one tutorial )

1) It is very important and necessary to define accurately

*in 2D geometry. I do not know this parameter. how to calculate it. my geometry is very simple, just a rectangular to 10*20 mm.***Source Correlation Length**2) What should be the

**? In 2d-cylindrical tutorial, I read it is a cylindrical wall. My geometry have 0.5 mm inlet a bottom. Is it the source zone and type will be Velocity INLET ?***source zone and type*3) Where will be the

**? I have to monitor the the time history when gas passes through from INLET ? I read one paper there was one monitoring point which is away form the inlet.. I could not understand.***receivers position*4) What is

**? I think, the under investigation portion has very fine mesh. this is called FW-H integral surface. But I am not sure about it..***FW-H integral surface*Any type of advise, guideline or tutorial will be highly appreciated. Thanks in advance..

Dear all :

I'm trying to solve the following problem using COMSOL Multyphysics.

I have an enclosed geometry (please see the attached images) with a top flat surface (the celing) and an undulated shaped bottom surface (the floor). And I have Air as a medium enclosed inside this cavity.

So, I want to solve for fluid Velocities (u and v) distribution of the air inside the cavity, and for its Temperature distribution too.

So, I already included the

**physics modules**:**Laminar Flow**(for**single-Phase Fluid Flow**) and**Heat Transfer in Fluids**.However, I'm sure I'm doing something wrong witht he Boundary Conditions (it can be observen from the first attached image, that I don't get any velocities distribution for the air mass).

The BC I am trying to stablish are the following :

**i.**

**Isothermal Walls**in all the interior walls of the cavity.

**ii.**

**No-slip Boundary Condition**

**(u=v=0)**in all the walls (on the inside) of the cavity.

**iii.**A

**constant Temperature**at the upper flat surface

**iv.**A

**constant Temperature**at the bottom (wavy floor) surface of the cavity.

Where the problem could be at ?

**The Velocity Stream Lines and Temperatures Contours should show a kind of oval spiral pattern at the top of each of the 'valleys' of the wavy bottom surface.**But as depicted in the image, I don't get any valocities distribution.I will really appreciate if someone can give some help.

Thank you all !

Best Regards !

I am doing a numerical study of a new model of a heat exchanger and there are no previous studies on the same geometry that the study was conducted on. Is there a way other than conducting experiments to ensure the validity of the numerical study?

I am trying to calculate flow parameters of the multi stage subsonic axial compressor using Ansys CFX. But it turned out that the solver cannot find the solution. In all cases an "OVERFLOW" error has appear. I am trying to solve with following boundary conditions: 1) total pressure and temperature at the inlet and massflow rate at the outlet; 2) total pressure and temperature at the inlet at the inlet and static pressure at the outlet. On the other hand when i performing calculations of the separate stages, the Ansys CFX solver easily find the solution. As I understand it, when i try calculate all stages in one calculation, the initial parameters in the solver are too wrong and because the solver cannot find the solution.

What can I try do to find a solution?

Is it possible to take into account connecting wire(fig.1) in the fluid flow calculation of a turbine stage in the Ansys CFX?

While doing 2D simulation of underexposed and over-expanded supersonic jets my results is getting converged with low NPRs (2-4) with choosing Zero Supersonic/Initial Gauge Pressure at the inlet of nozzle in the Fluent solver. But it get diverged with high NPRs (4-10) value. However results are converging when putting nearer value of Supersonic/Initial Gauge Pressure to inlet nozzle pressure. Kindly help me to resolve this problem ?

I need to simulate the transition of Flow through Coarse Porous Media such as Rock-fill dams, to investigation of Water level profile in each distance from up-stream and determination of discharge of fluid seepage from the body of these media. Notice, I want to simulate a Single-Phase Flow.

How can I simulate this project? Please suggest and introduce a useful software for this issue to me...

What is your idea about Flow 3D, Fluent, ABAQUS,...

Conference Paper A numerical study of the flow through coarse and homogeneous...

Conference Paper Transition of Flow through Coarse Porous Media with Network ...

I want to know if Ansys Fluent is an appropriate tool for modeling river bed sediment transport which is a frictional particulate flow regime rather than a collisional regime such as fluidized bed. Fluent has a DDPM-DEM model that can be used, however, I couldn't find any studies that have been used Fluent for this purpose. Thanks

I make calculation of my model of finned heat exchangers by Ansys Fluent. Model is somewhat complicated and have abut 5 millions elements and 8 inflation's layers. I chose k-epsilon method for solving and choose pressure outlet and velocity inlet for air (1 m/s).

On outlet is appeared reversible flow on great amount (see atachment). What is reason?

How to eliminate this reversibilke flow?

Did i make some mistake in input data?

When the buoyancy effect is significant in supercritical fluids passing in the tube, some eddies can form in any location of tube, especially at the vicinity of supercritical temperature. So, what is the numerical method to solve like the compressible problem? As my experience and literature, there is no way to calculate this type of problem by using RANS models, so I have just started using LES models. Although it was used a very low time step size (about E-5) and tried all of the subgrid models, I couldn't solve this problem. I would like to be grateful if you could share your recommendations. Thanks

I had to calculate parameters of the technical oil flow in Ansys CFX.

To solve this problem, I used "the Turpentine" (from Standard Ansys CFX material library) as the working body.

Is it right ?

I know the actual density of the oil. The Turpentine has similar density. Is it enough to use"the Turpentine" as working body?

In our experiments with shear-thinning supensions, should we consider the viscosity change with change in shear rate? E.g., capillary number (Ca) and Reynold's number (Re) both contain viscosity as well as characteristic velocity for viscous forces. We are varying the flow rate and so the shear rate changes. Should I change the viscosity accordingly? Or is using a single value is fine?

I'm guessing this is an issue with experiments and not with computational work where the formulation is usually non-dimensionalized and one can simply vary the Ca or Re directly.

I was trying to solve channel flow with fully developed flow at inlet as well as outlet using simpleFoam. I would like to know how to implement periodic/cyclic boundary condition (translational) in inlet as well as outlet.

Can any one help me how to implement this boundary condition?

Dear

I am simulating the natural convection in circular annulus through magnetic field. For that I am writing udf for x direction magnetic, kindly share your valuable experience in doing such a task?

How can I debug the code written in UDF File?

Can some one give me details for the application of QUICK scheme to 2d lid driven cavity?

Best Regards

Trying to find any benchmark on the drag coefficient for a cylinder in axial flow. There are many on the flow from the side, also several on axial flow for Re over 10000. What about the near-Stokesian regime?

Hello

I am solving sub-cooled boiling flow with CFX. I do not want to use single phase wall function. I want to solve the viscous sub-layer. Is it possible? If so which turbulence model is suitable? Which points should I take into account?

Thank you

Hello Everyone ,

Hope you are doing great .

I am simulating a 3D wing of aspect ratios

a) 0.5

b)1

c)1.5

d) 2

Why is it so that as I move from AR=0 to AR=2 the difference between CFD and experimental results increases .

Regards

Aamir Sultan

Hello Everyone !

I am simulating a 3D airfoil at higher angle of attacks (post stall regime) . I wanted to know that is RANS formulation capable enough to resolve tip vertices or not .

Regards

Hello Everyone ,

I am running a 3D simulation of an airfoil . The results I am getting for drag or lower than that of experimental results . I wanted to know could I calculate the value of lift induced drag from drag polar ?

I am simulating (CFX) a pipe with a turbulence promoter in it. I am using RNG k-e turbulence model yplus is lower than 1. For mesh independency analysis I am using turbulence kinetic energy as a output. The problem is, as I increase the mesh size, relative difference is getting higher up to certain mesh size (solution is getting mesh dependent). After that mesh size the relative difference is decreasing. For example from 4 to 12 million, relative change increases and from 12 to 25 million, it decreases. This values are coming because of the region where is just after the turbulence promoters (dominant anisotropic flow).

What could be the reason?

Hello Researchers',

I am working in computational fluid mechanics problems that investigate the effect of dialysate concentration and flow rate.

Q1: what is the maximum net osmotic pressure (MPa) that we can apply on membrane BC as driving force to the mass transfer along the membrane surface or maximum solute mass fraction for the dialysate (k_gsolute/kg_solvent)?

Q2: why the dialysis flow rate limited by 800 ml/min and some publishable journal used 1000 ml/min and not more than this flow rate?

Q3: what is the clearance of urea or uraemic toxin during one session of hemodialysis in (kg/m^2.hour)?

Thanks in advance for you and if you can provide me with a study/studies that have these pieces of information.

I am working on enhancement of heat transfer in a square channel through broken ribs. I need to calculate friction factor f so I need pressure drop across the periodic duct. I am using FLUENT 6.3.26 for simulation with periodic and symmetric conditions. The upper and lower walls are heated walls where constant heat flux of 2500 W/m2 is applied and other two walls are adiabatic, and adiabatic ribs were provided on heated walls. I am using the k-ep turbulence model. Is there any other method to calculate friction factor in this case?

I am trying calculate a steam turbine stage which works in wet steam zone. But i dont know how define boundary conditions: in Ansys CFX, because i can define only Temperature and Pressure.

Temperature and Pressure are not enough data for wet steam, because Temperature and Pressure are equivalent in wet steam zone.

I need additionally define enthalpy or wetness,but i stuck to do it.

Can anyone tell me how do it ?

(P.S. I am use Steam1 from IAPWS-97 library)

i am simulating a pulsatil blood flow inside abdominal aortic aneurysm AAA witch is unsteady (cardiaque cycle ) , Fluent gives differents parametres ( velocity , pressure , wall shear stress WSS... ) at each time steps ,but i want to calculate OSI oscilating shear index witch depends on the mean and the magnitude of WSS wall shear stress in the cardiaque cycle ... is there a way i can do to calculate OSI in Fluent ?

Right solve or not, if during all iterations Ansys CFX Solver manager writes, that he set up artifical wall on the outlet (in my case) ? Howewer, all residuals has attained the level required and mass flow rate at the inlet equal to the mass flow rate at the outlet.

I'm looking for experimental data about the free surface elevation downstream of a horizontal cylinder in shallow water flow. Ideally for different Froude- and Reynolds numbers in a 2D setting. I'm not interested in the detailed flow structure, only the free surface shape is relevant.

Does anybody know some literature/papers?

For a submerged hydrofoil (Duncan 1981, 1983) such data is available.

Thank you

I'm trying to calculate valve of steam turbine in Ansys CFX (i'm using single phase material - water ideal gas).I'm getting that the mass flow rate in the inlet zone is not equal to the mass flow rate in the outlet zone when calculating half closed valve. This difference amounts to 20%. Howewer, the mass flow rate in the inlet zone is practically equal to the mass flow rate in the outlet zone when calculating fully open valve.

By comparing the displays of CFX-Solver-Manager,I noticed that , unlike when calculating fully open valve, residuals are not declining when calculating half closed valve (fig.1).Therefore, i think that calculation is not right in this case.

Also, by comparing flow structures, I noticed that ,unlike when calculating fully open valve, there are vortex zones (fig.2). I think, that this vortex zones are cause of error.

Please can you tell me how to raise accuracy of calculation of flow with vortex zones?

I want to optimized my basic design of a new kind of VAWT blade.

By applying the Buckingham Pi theorem, dimensionless parameters such as Reynolds number (Re) and Froude number (Fr) can be indicated for the two-phase flow.

Can I use the CFD FLUENT approach to investigate and examine these dimensionless groups for the two-phase flow patterns predictions and How? Is there any suggestion please.

Can somebody help me in Installing and starting of LAMMPS? I have completed all the steps in online guide of LAMMPS for windows but stuck? I am installing LAMMPS for DPD simulations.

Which programming language is the best to use in CFD?

FORTRAN, MATLAB or any other?

Is there difference between the performance of these codes and applications such as OpenFOAM?

Are the equations of Fay and Riddell embedded in Fluent or do they have to be imported using a UDF?

As usually the trend is a Courant number (CFL no) can only be used for a Transient( Unsteady) flow condition.

Thank you in Advance.

Dear Researchers,

I am working on simulating shell and tube heat exchangers using ANSYS Fluent. I have the huge number of tubes and it is not recommended to model it. Therefore, I am trying with alternative approaches like porous medium and heat exchanger models.

*In the porous medium approach, the non-equilibrium thermal model is recommended for heat exchanger type of problems.

*In heat exchanger model, dual cell method is used to simulate shell side and tube side flow and heat transfer.

I request you guys to help me in this regard.

Thanks in advance.