Aerospace Engineering - Science topic

James Garry Sir, Appreciate your words.

Trying to focus on reading and thinking wider.

still awaiting criticism

Dear Prof. Lev Kurlapov,

Thanks for your suggestion but it's not related to one....

In brief, I am seeking "Onboard Triggering using Accelerometer during Captive Flight Testing".

Regards

specific changes that you can make to your dynamic mesh settings:

For your specific project, you'll need to do some research to determine the best method of coding and programming in order to finish the analysis of the cantilever composite plate. The method of finite element analysis (FEA) is often used to model and solve complex engineering problems such as those involving the analysis of complex fluid dynamics. FEA allows for a highly accurate approximation of physical problems based on discretization and numerical integration of the equations of motions. Some popular software packages for FEA application are MSC Patran for the modeling language, Hawk-I for the computational engine, and Abaqus for the post-processing tasks. You can then look up tutorials online that provide step-by-step guidance on how to code a finite element analysis (FEA) of a cantilever composite plate. Most examples will involve employing a computational grid to discretize the problem into elements with associated properties, using a stiffness matrix to relate force and displacement, and expressing the equations of motion in terms of a numerical integration. Once you've completed the FEA analysis of the cantilever composite plate, you can then turn your attention to the next step of flutter analysis. Flutter occurs when an aerodynamic force causes a structure to become dynamically unstable. The process of flutter analysis involves using post-processors such as ABAQUS to analyze the data from the FEA procedures and to calculate the critical speed at which the structure can become unstable. I hope this information has been of help to you and good luck with your project!

Clearly, researchers will come down on both sides of this question. I go back about 40 years in the Computational Science field. My choice is to write my own solvers whenever possible. For me, it is very important to understand the details of how the solver operates so that I may identify any numerical pathologies that occur. All intricate computational physics algorithms have difficulties; that is their nature. I have worked on both the research and applications side of this field. What I find is that when people get into the habit of just "running the code", they steadily depart from an understanding of the code. Of course, there is a balance that is in need of achievement. An engineer is unlikely to write his own code for the CFD or CSM analysis of a full aircraft, yet he or someone on the "team" must understand how to judge a commercial code's behavior. With that in mind, I will stand my ground, the best way to learn is to study the algorithms and write your own suite of computer codes.

Thank you for a detailed response. I could not find the resources you've mentioned but I did find other papers on the MLS method.

Drop Weight Impact Testing Machine is available in VIT it self. Please verify it once again before going 2 other college sir. All the best.

Thank You very much Ram Tenneti !!

Follow the lead

When using Abaqus or other finite element analysis software, it is not uncommon to encounter elements that become highly distorted and remain connected by only one node. This can occur for various reasons, such as meshing errors, modeling inaccuracies, or material instability.

To address this issue, you can try the following steps:

The type of University would hardly matter if your Ph.D. topic is unique and work is free from any synonym of copy and you have followed the standard norms like publishing min three papers in Scopus Indexed journals and patenting your work etc. Ultimately the doctorate person will be judged not on his face vale but on the basis of his knowledge and work.

Thank you for sharing the finite element model. Do you consider additional constraints such as natural frequencies, moments of inertia, center of gravity?

Dear Aravind,

You are welcome.

Regards

Aditya Kumar Mishra Scientific answers are already cited by many experts aI can say depending upon the simplest form is that Energy is nothing but ability to do the work......

Dear Thomas

Hope the link and appended document will help

Time step size is the minimum division of the time on which the maximum iteration you have given is going to perform. If you have to run a simulation for 200 seconds then you have to take the number of time steps 2000 for 0.1sec time step size or number of time steps20000 for 0.01sec time step size. Whereas the maximum iteration/time step should be taken as 10-20, wherever the values of residuals are converging.

As you mention... know how to model the vortex shedding problem in Ansys-Fluent. For a study of vortex shedding the important requirement is the frequency and the proportionality factor for vortex shedding is named Strouhal number.

I think setup a few points in the wake region for u-components and that should fluctuate with a certain frequency, Try to use FFT and mark your needed frequency from that.

Thank you for answering

What I understand from the above two answers is

by looking phase diagram, at AA temperature (150-180⁰ C), the solubility of Si in Aluminum gets zero but in Al10SiMg because of Mg content Si is not precipitated and forms Mg₂Si

Correct me if I am wrong

Hi Saeb AmirAhmadi Chomachar

Thanks for showing the disturbance suppression capability of your proposed controller. However, I'm unsure what you meant by "injecting a step-function as a disturbance input". The disturbance is a sinusoidal signal.

I have tuned the PD gains so that you can compare both of them meaningfully. The setpoint or the reference target value for the process variable (x) of the double integrator is 1. The double integrator is also loaded with a sinusoidal disturbance of 0.1*sin(t).

x'' = - Kp*(x - 1) - Kd*x' + 0.1*sin(t); x(0) = 0; x'(0) = 0

where Kp = 0.002304, and Kd = 0.096.

The final value of the process variable (x) oscillates within the magnitudes of 1 ± 0.1.

I implemented the simulink - flightgear interface from scratch, and without relying on the dedicated toolbox provided by Mathworks.

Please feel free to check it out here.

Thank you for your answer dear

I really appreciate your suggestion. Unfortunately, the authors were using an averaged model, which is not the case i'm looking for.

Look here for some reference information:

HIL or 'hardware-in-the-loop' testing is by its very nature a resource-hungry solution to testing, requiring multi-skilled teams able to set up and configure both the execution platform and the I/Os as well as the modelling environment.

Once your model is verified (i.e., MIL in the previous step is successful), the next stage is Software-in-Loop(SIL), where you generate code only from the Controller model and replace the Controller block with this code.

For more detail, we have :

Okey the inertia is assigned if you define the bullet or impact object as discrete rigid. Because Abaqus wont let you assign a material to the object so no density will be given to it.

Dear Dr.

Yes, this is a work of modern methods. For delicious reasons, adding nanoparticles has many advantages. It has the ability to improve the performance and emissions in the engine as well as improving the thermal behavior of the engine. Adding nanoparticles to improve Oil by adding these materials to the lubricant oils. There are many advantages.

Best Regards

Absolutely right sir. @Mr.Russel King.

Thank you.

You can study end wall profiling in either of the two rigs you suggest. And as you say the annular one looks rather more like an engine. The use of incompressible flow is fine unless the "real" case you are simulating happens to be supersonic where shockwaves will cause steps in pressure that you cannot simulate at low Mach number. The important rule is that the design of your endwalls is carried out at the same Mach number as your experiment.

Back to your question about annular or otherwise. An important feature of annular cascades is that the spinning of the fluid at row exit is associated with a radial pressure gradient (as happens in engine). This pressure gradient transforms the nature of the secondary flow. High loss fluid will migrate radially inwards. This makes the suction side boundary layer and the loss cores fall towards the hub suction side corner. If your design focus is to modify the end walls only then you cannot address these radial flow effects satisfactorily. This means that the proportional reduction of secondary loss is reduced. How ever the general rule is that the stronger the secondary flow in the initial geometry the stronger the potential benefit of endwall optimisation. This suggests that having a cascade of low aspect ratio will make the secondary flow worse, but the improvement better.

Good luck either way

Martin Rose

Dear Adhithya Babu,

A successive convexification algorithm designed to solve non-convex constrained optimal control problems with global convergence and it can handle nonlinear dynamics and non-convex state and control constraints. However lossless convexification cannot handle nonlinear dynamics. For the third question the answer is affirmative.

For more details and information about your questions I suggest you to see links and attached files on topic.

Best regards

How to set the initial condition in ECEF? Can you elaborate the answer how you varified the satellite positions exactly?

Corresponding Python script

Dear Muhammad

Besides not being answer to your question, I do not know how to answer. We developed our own computer programs to deal with variable geometry compressors, turbines and propelling nozzles. These components are designed and their performances calculated using our own software. A set of compressor, turbine and propelling nozzles maps are synthesized (one each for different angles and interpolated for angles not covered in the maps). It is not difficult task, but takes time to develop, verify and certify every piece of software.

Yes, we do have to know about the spaces, at least during our university studies, to enables us to expand our mind into abstact level, that will be very usefull for design activities

Hello Al, if I understood correctly the problem you described is known as Lambert's Problem. I am not aware of a specific software, but I know of two great solver scripts that can be found on github:

In Python:

In Matlab:

If you look for Lambert's Problem or Lambert solver I'm sure you will find code for other languages as well.

All the best!

A nickel material "as strong as titanium but four to five times lighter".

Other related articles:

Regards,

Joachim

Yes, I recently heard that the Scandinavian countries have taken good steps. A clear future is waiting for this area.

dear student kindly ping me at Jvmlal@ymail.com Ahmed Yassir Bouslalah

Which materials changed the History ? For example, carved stone, bronze and iron changed the History in its own moment, leading to the corresponding Ages of Stone, Bronze and Iron of the Mankind. These Materials allowed the fabrication of better tools that allowed in turn to control the environment (more intensive agriculture, more sofisticated manufactured goods). Cooked clays permitted storage that in turn permitted longer life shelf and water transportation, and the first buildings and writing pieces in Mesopotamia. Paper was another material that changed the History, allowing to keep the written words and then spread the knowledge. Then plastics, that made everything cheap but that become a nightmare latter (thus changing again the History).

Which materials will change the future? Not talking which compounds, but the types of materials we could mention: Bioinspired materials made with the architectures, functionalities and raw sources from biological things and smart materials that will react to the needs of the user or to the changes in the environmental conditions. These materials should come from sustainable sources or have to be so specialized that would allow their use in a profitable scale.

Hope you find these comments useful.

Dear Eng. Omar

If one imagines the wing as a cantilever beam under distributed vertical lifting force, which should balance the total weight of the airplane during cruising steady flight, the approximate formula for calculating the wing tip deflection may have the form:

Delta(Tip)= F.O.S. * [ W b^3 / 16 EI]

where F.o.s.= Safety factor (1.2 - 1.5) for gusts and dynamic effects

W = Total weight of the airplane

b= semi span = length of the cantilevered wing

EI= equivalent bending stiffness of the wing cross section

(Depends on material of construction and second moment of area)

I wish you the best

Thanks

if you can generate the plots from mat lab code here is your sight 👉🏻 https://archive.org/stream/NASA_NTRS_Archive_19930091685/NASA_NTRS_Archive_19930091685_djvu.txt

If you want to build your own, then try editing the existing airfoil coordinates from airfoil tool.com and log in to “airfoil data base search”.

Thanks

Following

I think its good with www.freefullpdf.com

I recommend Firoz Ahmad 's answer

I recommend Frank's answer

I am agreed with Stephan C. Kaiser

I am agreed with Dr.Khaled Al-Farhany

In Hypermesh, either you can extract the mid surface or you can create a profile of the surface and generate the 2D mesh on that surface. Select the option spin under the elements and define angle, axis of rotation, base point and assign the 2D element created.

In Ansys (APDL), you need create 2D element on the same surface and rotate using 2D Axis – Symmetric option.

Hello, Do u know the relationship between the " sun direction vector" in solar load model and " beam direction "in the wall radiation boundary

The short answer is Fluent uses the CFL number to compute the time step (even for steady flows). A more detailed explanation follows...

The coupled set of governing equations is discretized in time for both steady and unsteady (transient) calculations. In the steady case, it is assumed that time marching proceeds until a steady-state solution is reached. Temporal discretization of the coupled equations is accomplished by either an implicit or an explicit time-marching algorithm. In the Explicit Formulation the time step is computed from the Courant-Friedrichs-Lewy (CFL) condition. The time step is a function of: the cell volume, the cell face area, and the maximum of local eigenvalues.

Here is some additional information straight from the theory guide (Fluent Version 6) in the section: Steady-State Flow Solution Methods.

For steady-state solutions, convergence acceleration of the explicit formulation can be achieved with the use of local time stepping, residual smoothing, and full-approximation storage multigrid.

Local time stepping is a method by which the solution at each control volume is advanced in time with respect to the cell time step, defined by the local stability limit of the time-stepping scheme.

Residual smoothing, on the other hand, increases the bound of stability limits of the time-stepping scheme and hence allows for the use of a larger CFL value to achieve fast convergence.

The convergence rate of the explicit scheme can be accelerated through use of the full-approximation storage (FAS) multigrid method.

Hope this helps!

a lot of the above will depend heavily what industry you look at as there are basically unlimited application examples, and no single source can cover metallurgy, semiconductor industry, building industry, medicine, pharmaceuticals etc.

Hi following applications can be noted: Electronic device cooling, transformer cooling, silicon mirror cooling, vehicles cooling, controlling fusion, nanocryosurgery, magnetic cell separation, drug delivery, cancer therapeutics, cryopreservation etc.

Hello

Isotropic turbulence means that there is no mean shear, rotation or buoyancy effects in the flow as this can lead to anisotropy.

Homogeneous turbulence means that there are no mean flow gradients.

In another way isotropy deals with invariance in rotation and homogeneity deals with invariance in translation.

Isotropic flows can have a homogeneous or non-homogeneous microscopic structures.

In many cases, the flow can be A homogeneous and anisotropic . The Homogeneous Anisotropic Turbulence (HAT) is observed in many problems, such atmospheric flows…

Regards.

thanks ,

20 db for which application, mean for communication ,actually more than 50-60 antenna uses for a aircraft for different application.

Never Mind I solved it. But thanks for thee paper.

Dear Steffen,

the theory states that higher the compression ratio higher the engine efficiency. However, in real applications this is limited by the escessive combsution noise that can lead to excessive engine wear. In addition, for higher compression ratios, the combustion temperature will increase leading to higher NOx formation by thermal mechanism. The advantages and disvantages will be also related to the type of combustion that you will use. In general, for any combustion, the disavantages are that you are increasing the mechanical demand, forming more NOx and reducing your control on the combustion process whilst yo are increasing the thermodynamic effiency and reducing some pollutants as unburned hydrocarbons.

Best Regards,

Rafael

Copy the principles of a car chassis to suit your needs.

Try to have a low centre of mass and a wide wheel track to help stability.

Use strategic, short struts to add torsional stiffness instead of using much larger sizes of wood.

Using some type of suspension component will allow much lower stresses on the frame but may be practically impossible.

Depends what one plans to do with the PMSE data. For example, if goal is to investigate the wave activity in the summer mesopause region, probably Doppler velocity is the best to use. If one plans to do a statistical analysis about the phenomena itself, I do not expect big difference using SNR or volume reflectivity. Spectral width is used sometimes to highlight the turbulent areas in the observed region.

So, important is to define the interest of research whether assume PMSE as a tracer and use it to study dynamical processes or obtain background wind, or purpose is to investigate the PMSE morphology, micro-physics etc.

Often the simple answer is that depends on the "tradition" of the code.

Then, "better" is too general. We should focus on accuracy and computational cost and hence on the resulting efficiency. FEM is somehow less efficient than FVM for higly non-linear flows but recently DG method received new attention in the CFD community.

Finally, I would stress that FVM is nothing else that a FEM for a specific choice of the test-function.

check Fig 4

If i may add my 5 cents to this:

--> Depends how you want to see Elon Musk: as the visionary who wants humanity to thrive and improve? Or just as the one who seeks fame and fortune for being the first in doing things?

In my humble opinion, humanity has yet to reach a level of mindset to overcome cultural and religious differences. We might have satellites and smart phones, but in our thinking we still behave like cave-men.

For example, the Americans, when setting foot on the Moon, put an American flag there. Not one showing Earth. How would it be on Mars, when Chinese, Indians, Europeans and Americans set foot there? Whom will it belong to? For sure not the entire humanity, so we would just bring all of our archaic thinking into a new world. All our problems and issues, and soon the new planet will suffer all the same problems as we have on Earth.

As long as we do not manage to live as one humanity on one planet (i.e. having a global government), there is no point in making humanity multi-planetary.

--> As mentioned above: if you want to colonise something, who does it belong to? Is there indigenous life (whether intelligent or not)? Or is it a barren rock?

Now given the barren rock case: Who does it belong to? Imagine it has a huge amount of rare minerals on it. Is it "whoever finds it can keep it"? In the outer space treaty from the 1960s, they addressed this topic, saying that space belongs to all humanity, yet not all nations have signed this and yet when it comes to mining/farming/inhabiting these space environments, how is that regulated? And if violated, who prosecutes the violators?

There is a huge legal issue in regards to occupying space environments.

Now given the planet is not a barren rock, but an obviously inhabited planet: Now we can either develop yourselves as species and not touch the ecosystems of these planets, leaving them pristine for the indigenous life. Or we can act in the human way and do the same mistakes as we did in the past over and over again and just go there, exploit and trash the planet until its depletion.

The most difficult and realistic case is actually the case of Mars:

Why is Mars so interesting? Because in its past it was very similar to Earth, it had a denser atmosphere, a magnetic field, volcanism, starting plate tectonics, liquid water and all chemical ingredients for forming life. Mars might have gone through a similar evolution as Earth, forming microbial life, or maybe even be the origin of terrestrial life, as interplanetary transportation of rocks after impact events is proven to occur. Now, Mars is the perfect (and maybe only) place to actually study how life on Earth could develop and if life could develop on other planets as well, if life is unique or if it appears quite common throughout the universe.

But, if we send now a bunch of colonists there, who will bring lots and lots of organic material from Earth, we might spoil Mars to a degree where we cannot study this anymore, loosing a very unique opportunity.

Given the case there is still life around, wouldn't it be best to first study it, before building houses, schools and hospitals next to it?

And then there is another ethical consideration that needs to be taken into account:

Sending colonists to space with current technologists would use up significant amounts of terrestrial resources. Sending just 30000 colonists to Mars would already use up all the remaining mineral oil reserves on Earth, not to mention the metals, materials, supplies, etc shipped with the settlers. In order to send these few privileged people to Mars, the rest of humanity will have to sacrifice their lifestyle, their future and their environment. Is that ethical?

--> If we could terraform Mars, why not first terraform Earth? Reverse the effects of climate change, stop and reverse desertification. Earth is better studied than Mars, but as long as here high-ranked people make money with pollution and deny scientific facts, nothing will happen for the better. The money that Musk wants to spend on the colonisation could as well be spent to cover parts of the Earth's desert areas with solar power plants, providing humanity with CO2-free energy. That would benefit more people.

Also, terraforming Mars will not be sustainable. Mars is loosing its atmosphere, because of the lack of a global magnetic field. it might become a home for a while, but thinking into the far future, Mars will be back to where it is now.

Plus, how do we know we can potentially manage to create stable living conditions on Mars, when we are all about destabilising every environment we enter?

--> Maybe because it is easier messing up something new, rather than fixing something old?

--> Musk's rockets use RP1 (refined kerosine) like all other rockets, and as long as this remains the cheapest fuel, nothing will change. Rockets are basically 95% fuel that is burnt. Using synthetical fuels is a huge cost factor. And especially since the CO2-concentrations (despite being high enough to significantly influence the climate) in the atmosphere are too low for economical use, I do not see any of this happening any time soon.

--> No. We need to politically, economically and ecologically get our shit together first. We need to all reduce our negative imprint on the environment on Earth, foster international collaboration not wars, fear or hate, we need to change our thinking not towards maximising the monetary output, but in maximising our own happiness and humanity towards others.

Also, we should (must) explore Mars first. The right step is to first send a small groups of astronauts to carefully study Mars (and come back) over an extended period of time (~20 years) to really answer all our open scientific questions, before we can even think of inevitably spoiling the pristinity of the planet.

==> this would be the right way, and would avoid many of the mistakes that human explorers on Earth have done in the past (i.e. settling at their first arrival to a new place)

You should consider every space as a volume between 2 resitors: the one supplies a flow fucntion of the pressure difference and the other leaks as well in proportion to the pressure difference. All the inter teeth spaces are in series and all of them between high and low pressure. Depending on viscosity you may have to consider as well in the gap between toth top and housing a transprt flow proportional to the sliding velocity..

Import the file to Tecplot, and probe several points on the shock wave and the reflection wall. Computer the angle by the coordinates(tangent function).

Best

Dear Zouhir, you write "But software only determined this according to the formula.

formula is: D= (E1*b* (d^3-c^3)/12"

Yes, this formula is commonly used for determination of bending stiffness of bars made of homogenious materials. Are you want to find analogical analytical dependence for determination of bending stiffness of sandwich bars as well for determination of shear stiffness of sandwich bars?

As for experimental technique,  I agree with Pouyan Ghabezi that three-point bending test is the simplest way to find flexural (bending) stiffness of a sample.

Good luck,

Serge 

I'd use commercial 3G-4G mobile phone networks in order to send and receive short communication lines that help upload discrete commands (eg. Speed, Altitude, Go to a preset waypoint, Cancel mission, Go back home....) and download basic status information. Wouldn't work for downloading real time imaging, but maybe acquiring some basic environmental information.

This site is not a platform for you to get answers to your homework. Try doing the question yourself and making concrete questions based on where you have trouble rather than wasting the time of professionals. 

The Y+ value depends on the turbulence model you are using. if you are using a turbulence model with a wall function then the Y+ value must be in a range from 30 to 100. However, if you are using a turbulence model, which doesn't need a wall function (more accurately, the turbulence model resolves the boundary layer) the Y+ value must lay in a range less than 5. Another point that must be considered here is the behavior of the fluid flow around airfoil at high angles of attack. because in this range the flow is an-isotropic and the Reynolds stress turbulence models are more favorable to be used. The usual two-equation models (such as k-e e k-w) fail to capture the fluid flow characteristics at high angles of attack, since they are based on the assumption of isotropic behavior of turbulence.

Please find the paper here:

Good Luck

Please see the following paper: 

Good luck