Questions related to Aerospace Engineering
I'm getting exhausted and losing hope to walk forward about my studies and research. I'm majoring in Aerospace Science and My Study area is Developing Materials for Aerospace Engineering. I am lost and giving up !
Any suggestions or Any guidance ?
In this pre-print, I present my personal exploration of the definitions of "infinite" and "finite."
Feel free to criticise and write as comment or email mentioned on the paper
To gain a deeper understanding of the context, you can refer to my previous publications: • 1. Shaikh, H. M. I. H. (2023, November 1). "Hypothesis and Experiments: Quantum Roots: 'E' as the Common Origin of All Existence." [DOI Link](https://doi.org/10.31219/osf.io/976rp), DOI: 10.13140/RG.2.2.35936.25607
• 2. "The Essence of 'E': Unveiling the Infinitely Infinite" by Haque Mobassir Imtiyazul Haque Shaikh, published in the International Journal of Frontiers in Multidisciplinary Research (IJFMR), Volume 5, Issue 5, September-October 2023. [DOI Link](https://www.ijfmr.com/papers/2023/5/7494.pdf)
definition of finite and infinite existence helps my hypothesis that in the formation of universe, finite and infinite both have played the rule.
Kindly let me know your first honest reaction, what that would be?
I'm currently facing negative cell volume detected error because of weird mesh deformation, ig I might have made mistake in the dynamic mesh setting but I'm unable to pin point my mistake. Also the simulation occurs for a few time steps with ridiculous values of lift and drag coefficients. I'm attaching below the pictures of deformed mesh, lift, drag coefficient curves, my smoothing and remeshing parameters too. Also I'm using a udf to give motion to the cylinder body. The frequency defined in the udf is 1. I had created a total thickness inflation mesh around my cylinder which is of 5 layers, growth rate of 1.2 and maximum thickness of 0.025. Hence, I first separate the cylinder along with the 5 layered inflation from the surface body, then I give the udf motion to both the cylinder and the 5 inflation layers that I had separated. Kindly help me regarding this issue as I've been trying to solve this issue since past 3 weeks, took reference of changing the time step from various articles but still I get the same error.
What references do you recommend? What theory should I use to model unsteady aerodynamics? Is it better to use software or coding? Please share some insights.
I'm looking to develop my knowledge to get hired as a stress engineer for my first job onwards. It seems like reinventing the wheel sometimes to try and understand how the software works. Is it bad / waste of time to do that?
I am writing a FEA solver (using MATLAB) for computing stresses and stresses in a 2D rectangular plate with an elliptic hole (rotated to an angle). I computed the global stiffness matrix using Gauss quadrature (3 gauss points) and have also calculated stress and strain in each element.
How do I calculate the nodal stresses from the element stress values. I think the element stress values that I obtained are calculated at the centroid of each element. How do I extrapolate/interpolate these values to get nodal stress and strains?
Please advise with some resources or tutorials or solved examples.
Myself Nekin Joshua R, Research scholar from Vellore Institute of Technology(VIT), Vellore. I need a drop weight testing facility.
Please let me know where it is available in India ( Preferably nearer to Tamilnadu and also suggest the testing facility all over india).
When we Launch rocket to put our satellite in orbit , how it is put in orbit so accurately? Because as I know their are debries in Leo, Meo & Geo so how they find their way out by going through debries , are their any radars to detect the debries , how they avoid this debries ??
I'm simulating a blanking process in 2D using Abaqus Explicit with ALE. When the Johnson-Cook criterion is satisfied, elements start to be deleted, thus simulating the fracture at the end of the process. However, no matter how much I try to initially distort the mesh so that it gets more structured by the time fracture starts, the element deletion propagates "diagonally through the elements" (see attached screenshots), which leaves some of the not deleted elements connected by just one node (again, see attached screenshots). This stretches those elements to the point where my stable time increment gets pretty low, my burr is distorted and large, unrealistic stresses appear. I've tried to make the mesh finer, which hasn't really solved the problem. I've also tried to activate DELETE DISTORTED ELEMENTS, but this option doesn't seem to work, as the elements get stretched but their characteristic length remains large, as well as their area. I've tried applying the minimium dt option of this tool with no success (as the only parameter that seemed to be altered by these distorted elements was the stable dt).
This question: https://www.researchgate.net/post/How-can-I-solve-the-problem-of-excessive-element-distortion-in-2D-modelling-of-blanking-process-with-Abaqus-explicit deals with the same problem but none of the answers given seem to help.
I've attached a couple of screenshots that showcase the problem. If anyone knows a workaround or has any suggestion they will be very welcomed.
Have a nice day :)
I like to do my Ph.D in mechanical engineering. My first option is Deemed to be University in India. And the Deemed to be university is approved by the University grands commission.
But some people are telling, studying in Deemed to be university is not valid. And telling you are not able to get a job in foreign countties.
Please clarify my doubt.
Hi. I'm going to optimize the layout design of the satellite with Abaqus and Isight. I designed and analyzed the Abaqus model, which is pinned below. Now I want to enter my model to Isight to optimize satellite, but I face a big obstacle. The Abaqus should enter the reference points and constraints points in Isight to optimize the parts' location, but there is nothing like RF points or constraints points. I couldn't find a way to solve this problem. May someone helps me to figure it out?
Hello Professors and researchers,
I am a new faculty member who has joined at Department of Aerospace Engineering, VIT Bhopal. The university is renowned for teaching in the country. As a person who has gained international experience in a german laboratory working as a scientist, and also a PhD from QS ranking institute, I now look forward to setup own laboratory dealing with research on Aerodynamics, fluid mechanics and CFD. I have published several papers in journals and conferences. I would like to know how one could setup own lab without much expenditure on facilities and R&D funding but has adequate access to student interaction (manpower only) free of cost. How can I start?
You can find the lab's details here: https://www.researchgate.net/lab/Aerodynamics-and-CFD-LaboratoryVIT-Aravind-Seeni
Please provide your suggestions. If you are willing to collaborator as well, a warm welcome.
Dr. Aravind Seeni
Q. : Students asked me that "we only study about different forms of energy, one form of energy getting converted to another forms of energy. But no one knows what is energy."
Ans: No answer
Q. Sir Why do we have to call something by the name that a scientists used long back, can't we change it.
Ans: Science or engineering is field of perspective, how one looks at something matters. But everything that you read in a book can be changed. If you wish you can express it in a different manner.
It is the terminology, that we learn, in which people who observed certain phenomenon used to explain a particular concept we follow. Learn. To make world understand what you have to say you have to first make them ready to understand. Otherwise no one would know.
In comparison with a flat plate solar air collector and solar air collector with 10-meter tube. Which one should be taken for air velocity measurement? Inlet air velocity, outlet air velocity, average, Ashrea standard or ....
Pressure loss is 275 Pa in tube collector.
How can I measure with hotwire? How and where should I put it?
The force transmitted to a beam part, due to an impact analysis, is shown in attached figure. The figure shows the beam shear force with respect to time due to impact. The maximum beam shear allowable is 1500 lbs, whereas during impact, the beam dynamic peak force reaches more than 2000 lbs (at time 3e-3, 4.5e-3 and 5.5e-3 seconds). Does this beam fail due to the impact loading? For this I was thinking to convert the dynamic force to equivalent static force to compare with the beam allowable (1500 lbs). Would it be possible to find the equivalent static force for this dynamic force shown? Thanks in advance.
I am an Aerospace Engineering student and I would like to work on a numerical simulation. As I wrote in the title, I would like to study the effects of wind on an industrial chimney. In particular, I already know how to model the vortex shedding problem in Ansys-Fluent. I would therefore like to know how to study the effect of these periodic forces on a chimney. Which program should I use? Which code should I use?
Thanks to those who will help me
I studied journals on SLM (Selective Laser Melting) produced Al12Si components
In that many authors used Solution heat treatment/ annealing.
but for AlSi10Mg they used T6 heat treatment
why can't we use the same T6 for Al12Si?
Your answers help me a lot
Thanks in Advance
As I know, the ordinary differential equation (ODE), xdot= -x^3+u, where x is the state variable, and u the control variable, is the control system associated to a falling object in atmosphere with viscous drag. I am not sure to be correct on that! Please comment on that!.
Update 1: xdot= -x^3+u, is called the hyper-sensitive system.
c.f.: A Collection of Optimal Control Test Problems: John T Betts.
Another example is velocity control for aircrafts in horizontal flight, which has an ODE evolution:
xdot=-x^2+u. Notice the attachment picked from:
Optimal Control with Engineering Applications; By: Hans Peter Geering.
I want to also know the real model associated to the control system described by the ODE: xdot= x^3+u. I guess more probably, this is associated to electrical systems.
Update 2: My own intuition says, positively damped systems as:
are mechanical. Meanwhile, negatively damped systems as:
You can yourself find some other examples in this regard.
I make a simulink file to link the FlightGear with MATLAB, i use Function Block Parameters, Sink Block Parameters and Generate Run Scrip. When i run simulink file i see this error:"The Mux blocks used to create bus signals diagnostic must be set to 'Error' to prevent modeling errors (see the Mux block documentation for more information). Open the Upgrade Advisor to identify and fix upgrade problems". So I want to know how can i solve this problem to run both MATLAB and FlightGear?
Assuming two-dimensional flow, I'm trying to implement a code for a quasi DNS problem. There is no doubt that i should replace the velocities in Navier-Stokes equation (NSE) with its equivalent velocities in the form of u=u_base + uf, where u_base is the steady state solution for NSE for the channel flow and uf is the perturbed velocity which varies with time. By the new definition of the velocities, one can get new extra terms in NSE, as a function of u_base and uf. My point is to find the fluctuation behavior with time so that i can calculate the growth rate and start an instability study for the flow field.
There are two forms of the new NSE, maybe more but at least these two were the common equations which i found in most of the researches which i read. The first one is in the form of du/dt + div(uu) = - dp/dx+ iv(grad(u))/Re where u was defined earlier. The second form is: du/dt + div(uu) = - dp/dx+ div(grad(u))/Re - omega x u.
Which one should i use for the purpose of instability studies?
Note: You can check the attached files for the non-conservative form of the two previous models.
I want to learn performing Structural Analysis for rotorcrafts and looking for some instructions on how to plot V-n Diagram and perform Loading Analysis, Stress Analysis, Damage Analysis, Fatigue etc..
Some references like AMCP 706-202 helped me out but I'm still looking for some more help.
And how can I get "ADS-29, Structural Design Criteria for Rotary Wing Aircraft"? Will it help?
I am trying to simulate the impact of a 9mm bullet into a composite metal foam (steel) panel.
I might ask more questions in the near future so if anyone with knowledge about the topic and free time wants to help me, feel free to contact :D
Previously I worked on combustion engines....
But now due to my new adviser, i want to work on nanotechnology...
I want to work on a subject that relates to both nano and engine ...
Do you have any suggestion?
NFF (No Fault Found) has the major contribution to reduce the operational availability, resources and increase the cost of Maintenance of any aircraft in aviation. The likely causes are human factors, maintenance training, faults reporting, fault analysis, corrective Maintenance and procedures. However, mitigating these issues are completely a tedious process wherein management skill can't achieve the desired results. So, what are the other parameters/ technical factors that need to be considered?
I am recently doing some research on the optimization of 3D contoured endwall. And saw some papers related on it.
But I am wandering which cascade should I choose to do on it, annular or flat?
should I have to choose annular because it is more like the real engine, (but my test rig is imcompressible)
should I have to choose flat cascade because the flow feature is more simplicated?
Considering the powered descent guidance problem for a spacecraft or launch vehicle - Early publications by Acikmese, et.al. used lossless convexification to solve the landing guidance problem using point mass dynamics.
Literature that dealt with the powered descent guidance problem using 6 DoF dynamics, also by Acikmese, et.al. proposed the use of successive convexification, with the reasons being that lossless convexification could not handle non-convex state and some classes of non-convex control constraints.
I have the following questions with respect to the above
1) Why is it that Lossless convexification cannot handle some classes of non-convex control constraints ? and what are those classes ? (e.g. the glideslope constraint)
2) What is it about lossless convexification that makes it unsuitable to operate on non-convex state constraints ,as opposed to successive convexification ?
2) Are there specific rotational formalisms ,e.g. quaternions, DCMs, Dual quaternions, MRPs, etc. that are inherently convex ? if so, how does one go about showing that they are convex ?
I would be much obliged if someone could answer these questions or atleast provide references that would aid in my understanding of the topic of convexification.
Using LEA-M8T receiver from U-Blox, I parsed navigation data and after computing user position, I found that something is wrong. I think I should verify satellite positions calculated first. How can I perform it? and If the calculation method is false, How can I calculate satellite's position? 4th Runge-Kutta is not enough... (ECEF in Td is differ from ECEF in receiver Time)
Hello, I am performing an undergraduate finite element analysis research project, and my current task is to find the shear center for an asymmetric C beam. Out of curiosity, how does one go about doing this? (picture of profile attached, I am also just taking a mechanics of materials course at my university as we speak)
I wish you all a wonderful day
If some one want to do off design simulations for variable geometry compressor engine in GasTurb , is it possible to see the performance of the engine at different kind of varying angles. Because as i know , GasTurb considers some default VG factors a, b and c with a=b=1 and c=0.01...The confusion here is , how to encounter different angles for VIGVs and VSVs..if it is possible , then can we get compressor map with designated angles....?
We know that mathematicians study different mathematical spaces such as Hilbert space, Banach space, Sobolev space, etc...
but as engineers, is it necessary for us to understand the definition of these spaces?
Hi, can anybody please let me know if there any software package for calculating planetary orbital element determination? For instance, if the position of two points (radius), true anomalies of the points, and flight time of a planetary transfer ellipse are given, then, how to calculate the line of apsides using a software? I understand that I can do it manually in the trial-and-error procedure, but I would like to use the software, if any.
I am looking for material which can replace aluminium in aerospace industry as i want material which will be having high melting point and must be light in weight. As i am looking at this from commercial point of view so if that material is easily available and cheap then it would be better. Especially Aluminium 7075
I'm a 3rd year BEng Aerospace Engineering student and looking for research ideas on aero-acoustics and aerospace
Which kind of materials changed history and why?
What is the future of materials?
which kind of them will have a big change in the future?
Do you know a professor or researcher that is working on the top and new research fields? If you know them or yourself is one of them, please introduce their or your new research topics and introduce them or yourself to researchers.
Thank you so much
I've searched in airfoiltools.com but it looks like they don't have it. Can somebody help me out?
I am trying to measure the forces involved in the impact of a spear on a ballistic gel target. I need an inline sensor to measure this (placed in the spear). The products I have found are either load cells of force gauges. What is the difference between the two and would either work for my application?
Design and testing of aerodynamics;
Evaluation of heat transfer of secondary air systems.
I am running a steady periodic propeller simulation using the MRF approach (60 deg, periodic). I have had good results by setting the blade zone as the rotational one and having the rest as stationary (Traditional setting for MRF as far as I understand) so my question is ... Do you have any experience with these kind of simulations but using all as rotating zones rather than using only one? Do you know if is better in order to see the vorticity behind the blade?
If I use all-rotating approach, part of the geometry has to be a moving wall since that part is not rotating in reality.
Of course I can try by actually simulating it but it takes time. That is why your answer might save me some days :)
Thanks in advance!
I have been working in cryogenic loop heat pipe that is used for space thermal control, and it works in 35K or 20K and it is mainly experiment observation. Now I want to change my research a little in cryogenic heat and mass transfer, is there some new and fresh research direction for suggestion?
Hello to research gate community. I'm simulating a solar collector. I want to calculate sun direction vector whereas the sun rays are perpendicular to the collector. But I don't know how I can do it. Would you mind please tell me about it and also about S2S settings (as a radiation model in Ansys Fluent)?
As usually the trend is a Courant number (CFL no) can only be used for a Transient( Unsteady) flow condition.
Thank you in Advance.
I need good and up to date resources to find out the applications of nanotechnology at industry.
I want to know that what are the applications and study fields of nanotechnology in Fluid Mechanics?
As I read about nanotechnology applications all of them related to Material Engineering or Chemical Engineering....
Dear all researchers,
Can we create a turbulent flow with the following conditions?
1- isotrope & non-homogeneous
2- an-isotrope & homogeneous
it may be Indian or other country aircraft. such as how much gain is required which specific frequency, dimension of foot print( as wings, cockpit, tail etc)
so that i can design a conformal array according to given requirement.
I am trying to simulate the Anti-roll bar mechanism in Nastran. I have got good results so far, meaning torque in the bar under rolling and no torque when leveled. During this the bushings of the bar were constrained in translational directions.
I want to transmit this force seen at bushing constraint to somewhere else. But the moment this connection is made and the constraint there removed, the force goes back to the suspension, making the anti roll bar ineffective.
I created this connection using a bar element having all 6 dof.
Can someone suggest a solution?
I need to construct a 3D wooden bicycle trailer for Kids. The weight of bicycle trailers must also be light!
I don't know where I should start? I thought I'd start from chasis, but what criteria should I use to construct a chassis,Children's weights? no more?
The task says that the 90% of material must consist of wood.
So far, different parameters e.g. Reflectivity, signal to noise ratio, power etc have been used to study PMSE echoes. Could any one suggest me the more useful parameter out of these three or any other they know ?
I want to know that what is the reason of the usage of FEM in fluid mechanics. Isn't FVM better than FEM?
Why some softwares like COMSOL sill use FEM?
Is FEM has any advantages over FVM?
Which is better?
I am trying to create an impact pressure probe to measure spatial distribution of free stream pressure of a jet plume exiting to a rarefied medium. I found out that sankovich pressure probes is best suited for my purpose. Kindly provide the dimensional details of the above mentioned probe.
I want to start a philosophical discussion and ethical debate on the reasoning behind why humanity should and must become a multi-planet species.
- What do you think is the most profound and captivating reason(s) that you have to justify SpaceX and Elon Musk's goal of making humanity a multi-planetary species?
Elon said during the 68th Annual ISC on September 29th 2017:
"I think fundamentally the future is vastly more exciting and interesting if we're a spacefaring civilization and a multi-planet species than if we are not. You want to be inspired by things. You want to wake up in the morning and think the future is going to be great."
I agree with him here, but I think there is something more profound and captivating that must be addressed with regards to becoming a species that lives on more than just one planetary body. Other questions we may want to consider to help us reach this answer include:
- What are the ethical considerations we must address before colonizing other worlds?
- Do humans really deserve another planet to potentially ruin, or even sustainably terraform, if we cannot even figure out how to sustainably balance our own home world?
- One might ask why doesn't Elon use his genius to create new technologies that will advance the human race by solving some of the Earth's worst problems?
- Has he simply given up on this planet and does he therefore want a clean slate to build up from?
- Does Elon think that technological advancements resulting from the drive to become a spacefaring civilization (i.e. propellant production via. CO2 sequestration powered by 100% solar energy systems) will eventually rebound to help the Earth?
- Must we start colonizing Mars now (i.e. beginning in the year 2022) like Elon's timeline suggests? Potentially, if we wait too long, technologies to reverse climate change on Earth may not have advanced enough without the excitement of being spacefaring...
Lets see what everyone thinks about this, and let's keep it civilized in here. Try and get real profound!
Analytical determination of pressures in the tooth spaces at the periphery from inlet to discharge
is there any other experimental method to determine the bending rigidity and shear stiffness of a sandwich (three-point bending test) outside Allen's method?
Allens method is described in his book "Analysis and Design of Structural Sandwich Panels" on page 258
question - Write an script m-file to simulate in Matlab a step response (see help step) of the controlled system with K = 1 and = 1. Tune the gain of the controller (K) until there holds that the overshoot of the system is 25 %. Show in your plot of the step response r(t), (t) and e(t).
During the last decade, satellites have become increasingly important. Telephone and television are just two examples of daily life applications.
A satellite has a life-span of about 10 years. After that, its components may fail or it may fall out of its geo-static orbit due to loss of kinetic energy. In general it will burn when it falls back to earth due to friction with the atmosphere (sometimes the satellite may not totally be evaporated which can cause considerable concern when nuclear material was used in the satellite)
Only a few places on earth are suitable for the launch of satellites by rockets or space shuttles. The weather should be favourable (clear sky, no wind, no clouds) and the political climate of the country should be "stable" and/or "predictable". This combination does not often occur in countries around the globe. Australia might be in this respect in an exceptional position. Therefore, it is important that engineers of Australia have some knowledge about rocket and satellite technology. In this tutorial we will focus on course control of a rocket.
The rocket (see figure 1) has an inertia of J = 1e6 [Nms2], a length of l = 25 [m], centre of gravity is located at 0.6*l from the nose of the rocket and a rocket engine that delivers F = 100e3 [N] thrust and can be changed in direction over angle [rad] (in this tutorial we will only address this one-dimensional course control problem of a rocket).
The angle of the engine, [rad], can be changed very quickly compared to the change in direction of the rocket, [rad]. Therefore, the dynamics of the angle control of the rocket engine can be neglected; it can be assumed that the angle can be changed instantaneous. The size of the rocket engine can be neglected.
For control of the angle of the rocket, (t) is compared with a reference angle r(t). The difference e(t) is fed into a PD controller with a time constant of 1 [sec] (controller = K*(s + 1), = 1 [sec]).
Figure 1, Course control of a rocket (one - dimensional)
I am analysing flow over wing but I found out that at low angle of attack between 0 and 10, the lift coefficient is reducing instead of it increasing with angle of attack while the drag coefficient is increasing. I will appreciate if someone can tell me what is the cause.
I am a new user of Ansys fluent and to CFD
Passive and active flow control methods have been widely used in aerodynamics for enhanced performance.But very few reports could be found on the application of these techniques to hydrodynamics. So my question is are these techniques applicable to hydrodynamic machines in which the working medium is incompressible fluid?
analyzing using ansys fluent , i considered a 3000 iterations of K-omega turbulent model , but while exporting data , i got the value of cd and cl for each iteration till the end , my question is , which value of cd and cl ill consider at the end ? is it the last iteration value , of at the steady unchanged values ?