Assalam O Alaikum from Rafeh

[zulu]

@war&peace @Verve yeh tum dono ki field ka hai?

 

[war&peace]

@war&peace @Verve yeh tum dono ki field ka hai?

Yeah I'm also aerospace engineer with an inclination towards mathematic so he is from my field.

Welcome, you will soon go blue and later red or maroon. I'm also an engineer thriving in this nascent Pakistani market, don't forget about me when you start your business here

I'm afraid that he may get disappointed from the politics and trolling atmosphere, policies & attitudes of the members.

 

[zulu]

Love to see both u start/contributing in any technical thread or discussing projects even just theoretical ones who knows which idea click for Pakistan like next gen fighter engines to LR-SAM ; ) and to hell with Pakistani media portraying black even in small proportion but things going in right direction Inshaallah acha hoga

Yeah I'm also aerospace engineer with an inclination towards mathematic so he is from my field.

 

[ssethii]

Yeah I'm also aerospace engineer with an inclination towards mathematic so he is from my field.


I'm afraid that he may get disappointed from the politics and trolling atmosphere, policies & attitudes of the members.

No one takes online forums / social media seriously except retards. one just need to skim through it and find what you want and leaving all the filth behind as everyone is entitled to their opinions.

OT: The man is right with the help of the Chinese industrial base and better industrial terms, Pakistanis can fully exploit their prowess in technology. The real challenge is not dealing with the neighbor up north but snakes within.

 

[Verve]

@Rafeh

Welcome brother. Anyone looking to contribute to the rise of the nation is in high esteem.

 

[war&peace]

No one takes online forums / social media seriously except retards.

That is the core reason behind trolling. We Pakistanis normally don't take anything seriously and only engage in trolling. I created many educational threads and our Pakistani members were least interested in them. But I find the swarming like flies on the most useless threads for trolling.

 

[war&peace]

Love to see both u start/contributing in any technical thread or discussing projects even just theoretical ones who knows which idea click for Pakistan like next gen fighter engines to LR-SAM ; ) and to hell with Pakistani media portraying black even in small proportion but things going in right direction Inshaallah acha hoga

Mate I have already tried quite a few times to educate our members about the very basics of aerodynamics and flight mechanics because it is necessary to understand how an airplane works especially when I see people making ridiculous claims and suggestions because they don't have the knowledge. Here are links
Introduction of basic flight aerodynamics and Flight Mechanics
and this
Introduction to Computational Fluid Dynamics (CFD)
But not many are interested and also the management does not encourage either.

Rest as far as the idea you are talking about, this is not a suitable forum at all for that and believe none of the people of the concerned organisation come here to get any inspiration because they have access to very high quality sources and brains and they have developed their internal resources which are much more advanced and there experts and professionals who have years of experience so I don't think they have time scour through this troll infested forum in the hope of finding something useful. BTW, I have not found anything genuine or that inspiring so far....the most technical discussion here I see is limited to discussing the regurgitated specs of a few weapon systems and as knowing the specs of a car does not make someone a car designer or an automotive engineer, the same analogy a lot more true for an airplane which is a lot more complex machine than a car.

However one thing we can contribute is raising the basic understanding of the system and to that effect I have made those threads (aforementioned) but I hope to find a few likeminded and similarly qualified people who have the will to contribute towards this goal.

 

[Max]

Welcome bro.

 

[ssethii]

That is the core reason behind trolling. We Pakistanis normally don't take anything seriously and only engage in trolling. I created many educational threads and our Pakistani members were least interested in them. But I find the swarming like flies on the most useless threads for trolling.

Perseverence and patience are the key words here.

 

[Rafeh]

Once again thank you everyone for welcoming.

@war&peace, Brother I genuinely admire your efforts to share, educate and help other understand aspects of aerospace engineering. I will definitely contribute whatever i can. I do have a busy schedule, but whenever time permits I'll add my own views on technical topics. Even though you may be disappointed that people do not here show enough interest in your posts on technical matters. It may be because they are sometimes too technical for many.

Lets' admit it aerodynamics is quite challenging even for those who are studying it, especially since we don't have yet a coherent theory of aerodynamics. What I means, we don't have coherent set of mathematical equations that allows us to analytically calculate closed form expressions involving aerodynamics forces and moments on arbitrary aerodynamics surfaces. What we have in reality, are a bunch of approximate theories to deal with specific situations ranging form lifting line theories to theories dealing with bodies of revolutions, lifting surfaces, spectral theories etc.
The end result is we are forced to use some kind of numerical methods (i.e. CFD) even for relatively simple geometries or use things such as linearized theories to say calculate aerodynamics, stability, and control derivatives (which basically tell us how under the assumption of linearized aerodynamics, how changes in geometry, orientations, control surfaces etc, will effect aircraft aerodynamic, stability and control characteristics). That leads to empirical models (specific to each aircraft and each aircraft company), wind tunnel and CFD based look up tables for aerodynamic parameters (e.g. aerodynamic derivatives) giving us an estimate of aircraft aerodynamic behavior for each given altitude, control surfaces's position, deflections due to flexibility, external loads or missile launches and so on. Meaning we have to actually set up each situation that an aircraft may ever encounter in real life, either in wind tunnel and/or CFD to find out what what aircraft would do in what situation. That's very costly and takes years to complete. Not to mention requires hundreds of people. Though increasing accuracy of CFD is making things much faster every year now then the previous one.

One the other hand, if there was a unified aerodynamics theory, then we would plug those equations specialized for our particular aircraft under consideration on the place where you have forces and moments in the equations of dynamics (i.e. forces and moments in newton's equations, generalized forces in Lagrangian formulations etc.). One then would NEVER need a single wind tunnel test. We would solve those equations of motion (most likely numerically) and get aircraft dynamic behavior from start to finish as we please. Better still, we would plug those in our flight control laws and we would have a highly responsive flight control system in no time. Aircraft engineering would be as easy as developing a ground vehicle which many countries can do with some effort.

Not to mention we would then jointly solve those aerodynamics equations along with electrodynamics and get to have a stealth design far quicker, far better and with far less effort.

Unfortunately we don't have such coherent theory.

What I am trying to say is, it is quite challenging to discuss how in the absence of a unified general aerodynamics theory for arbitrary aircraft configurations, we can understand aerodynamics as a coherent set of conceptual and/or mathematical model. TO new comers and people outside of the aerospace engineering, it all looks like a big mess.

I am just trying to give a reason, why many people may not have contributed more to your post out of shear complexity that they represent.

War&Peace, brother, You are yourself an aerospace engineer so you can understand and appreciate all this complexity but not many others would find all this so interesting, especially since all seems too much information at times.

Still I agree, we should discuss all this in understandable terms, help each other understand where we need to learn more and your posts are perfect place to start that process.

However, it is not true that people from Pakistan's research organizations don't come here at all. I know for a fact they do come here (many relatives and friends do). They may even find something useful to look up after reading a post or two here. You never know.

 

[zulu]

@war&peace Quite common here whenever i post on population control or FATF advantages/disadvantages its got buried under political garbage threads Start some thread love to read yours view on such LR-SAM systems also check this video too these guys use thrust vector control in their RC planes model kamal ky loog hain yeh (JetCat P220-RXi Turbine cost 4000$)

 

[Hareeb]

Welcome to PDF.

 

[war&peace]

@war&peace Quite common here whenever i post on population control or FATF advantages/disadvantages its got buried under political garbage threads Start some thread love to read yours view on such LR-SAM systems also check this video too these guys use thrust vector control in their RC planes model kamal ky loog hain yeh (JetCat P220-RXi Turbine cost 4000$)

While during my Bachelors at Embry I made several RCs and after starting my business and getting money it it for hobby I built many RCs even with jet engines and spent $10k

@war&peace, Brother I genuinely admire your efforts to share, educate and help other understand aspects of aerospace engineering. I will definitely contribute whatever i can. I do have a busy schedule, but whenever time permits I'll add my own views on technical topics. Even though you may be disappointed that people do not here show enough interest in your posts on technical matters. It may be because they are sometimes too technical for many.

Great..it is always good to have a company so. I have tried my best to make it as simple as I can and honestly I feel I did a pretty good job especially when I compare my thread on PDF with the sources (my notes and books)..By the way, my class mates used to appreciate my ability to explain things in simple and layman terms and often I used to get surround by my classmates post lecture to smooth out different stumbling blocks that they could not get grasp during the lecture... one of the areas was aeroelasticity where I had to explain the difference between resonance and flutter.. etc or to help them understand the Schroddinger's wave equation etc. You should go through my threads and please point what could be made easier ...

Lets' admit it aerodynamics is quite challenging even for those who are studying it, especially since we don't have yet a coherent theory of aerodynamics. What I means, we don't have coherent set of mathematical equations that allows us to analytically calculate closed form expressions involving aerodynamics forces and moments on arbitrary aerodynamics surfaces. What we have in reality, are a bunch of approximate theories to deal with specific situations ranging form lifting line theories to theories dealing with bodies of revolutions, lifting surfaces, spectral theories etc.

Mate, well can talk little technical so basically you're referring to NS equations and yes there is no closed form general solution but we can always simplify the equations for very simple flow cases and then we do go closed form solutions like Couette and Poissuelle, I have written codes to visualise and solve the moving lid cavity flow using statistical average methods and traditional CFD but yeah there is no closed form solution for that and can only be solved numerically.

I normally do not start with an arbitrary aerodynamic shape rather use known shapes to dissolve the complexity into a manageable task. My problem is not to show case my knowledge but share it with Pakistanis in a way that they can understand and they can truly appreciate how an airplanes works.

The end result is we are forced to use some kind of numerical methods (i.e. CFD) even for relatively simple geometries or use things such as linearized theories to say calculate aerodynamics, stability, and control derivatives (which basically tell us how under the assumption of linearized aerodynamics, how changes in geometry, orientations, control surfaces etc, will effect aircraft aerodynamic, stability and control characteristics). That leads to empirical models (specific to each aircraft and each aircraft company), wind tunnel and CFD based look up tables for aerodynamic parameters (e.g. aerodynamic derivatives) giving us an estimate of aircraft aerodynamic behavior for each given altitude, control surfaces's position, deflections due to flexibility, external loads or missile launches and so on. Meaning we have to actually set up each situation that an aircraft may ever encounter in real life, either in wind tunnel and/or CFD to find out what what aircraft would do in what situation. That's very costly and takes years to complete. Not to mention requires hundreds of people. Though increasing accuracy of CFD is making things much faster every year now then the previous one.

Bhai... we both know. I have worked extensively in wind tunnels in addition to work on theoretical and numerical sides. From Langraangian to Eulerian approaches and even molecular dynamics and statistical models like Boltzmann theory and then recovering incompressible NSE's using H-operator to extract and hence proving the equivalence.

 

[Rafeh]

While during my Bachelors at Embry I made several RCs and after starting my business and getting money it it for hobby I built many RCs even with jet engines and spent $10k


Great..it is always good to have a company so. I have tried my best to make it as simple as I can and honestly I feel I did a pretty good job especially when I compare my thread on PDF with the sources (my notes and books)..By the way, my class mates used to appreciate my ability to explain things in simple and layman terms and often I used to get surround by my classmates post lecture to smooth out different stumbling blocks that they could not get grasp during the lecture... one of the areas was aeroelasticity where I had to explain the difference between resonance and flutter.. etc or to help them understand the Schroddinger's wave equation etc. You should go through my threads and please point what could be made easier ...



Mate, well can talk little technical so basically you're referring to NS equations and yes there is no closed form general solution but we can always simplify the equations for very simple flow cases and then we do go closed form solutions like Couette and Poissuelle, I have written codes to visualise and solve the moving lid cavity flow using statistical average methods and traditional CFD but yeah there is no closed form solution for that and can only be solved numerically.

I normally do not start with an arbitrary aerodynamic shape rather use known shapes to dissolve the complexity into a manageable task. My problem is not to show case my knowledge but share it with Pakistanis in a way that they can understand and they can truly appreciate how an airplanes works.


Bhai... we both know. I have worked extensively in wind tunnels in addition to work on theoretical and numerical sides. From Langraangian to Eulerian approaches and even molecular dynamics and statistical models like Boltzmann theory and then recovering incompressible NSE's using H-operator to extract and hence proving the equivalence.

I was mostly explaining things for other readers who might also read the post. I do not mean to explain to you brother.

Also I did not mean NS equations, they are too general. But rather their specialized form for aerodynamics. Let me explain what i meant by unified aerodynamics theory in this context. what I meant was this: Imagine I have an aircraft wing, a set of surfaces of some sort. Then that surface(s) is described by some equation (or set of equations and associated parameters). can we specialized (i.e. modify) the NS equations for those arbitrary surface parameters. WE may still need to solve them numerically but can we at least incorporate complicated geometric information directly in NS equations (not talking about boundary conditions). Furthermore can we manipulate those resulting equations so that we can have expressions for aerodynamic forces or moments directly in terms of those surface parameters. IF we did, we would have then a unified theory of aerodynamics for arbitrary set of surfaces put together (say as an aircraft). WE could tweak those parameters and directly optimize geometry. A theory that allows us to calculate forces and moments directly (rather then find say pressure or velocity distributions from solutions of Navier stokes equations based on a given geometry and boundary conditions). What I meant was we don't have such an aerodynamics theory. That's sad as it means country like ours needs billions of dollars to develop an aircraft despite having very good engineers. Other than aerodynamics, similar problem crop up in other fields.

Also I was NOT at all implying that you can't explain in easy terms. I myself probably can't. I have not even read your posts at that time. I was saying it all can be quite complex for the new comer and they may find it hard even with the best of explanation. This is also true when studying for undergraduate studies. So you should continue as it will help people in the long run. Also personally I realized such interaction have added to my own understanding much more than silent readings at times.

I mean come on, it may occurs to many not involved in engineering, hearing after a Pakistani missile test, " all parameters have been validated successfully", that what are these mysterious parameters.

So I was explaining (or confusing perhaps) other readers (other than you I mean) that we get estimates of say aerodynamics parameters from wind tunnels (or CFD) and then flight test to see those parameters values are actually same as the one estimated on the ground in the wind tunnels. That's validates them for that particular batch of missiles (Or we need to update them with more accurate ones so estimate them directly using actual flight tests).

That those aerodynamic parameters let us things such as say how changes in fin angle on a missile will effect its behavior. this way may be some teenager will get one thing or two or at least would know that it is not all that mysterious. Demystified, they might even chose engineering as a profession and we need technical professional in Pakistan.

SO reading your post, I genuinely believe that you can explain in much more concrete and easier terms. I can't explain that well. May be I was unconsciously projecting my own inability on you in an indirect way. Though I never meant it. It happens. What we can't do, we presume, unintentionally that others can't do either. It normal human reactions. I myself can't explain well at times so I was seeing myself I guess.

Whenever I am free, I will definitely visit this forum and share my vies. But please do note for future reference, a lot of explanations are for other readers. They may read our replies to each other.

WE will definitely have more chats in the future, Insha-Allah. But do note once again that my explanations (no matter how bad ) are meant for others who might also end up reading the post, even when you are being addressed.

 

[war&peace]

I was mostly explaining things for other readers who might also read the post. I do not mean to explain to you brother.

Also I did not mean NS equations, they are too general. But rather their specialized form for aerodynamics. Let me explain what i meant by unified aerodynamics theory in this context. what I meant was this: Imagine I have an aircraft wing, a set of surfaces of some sort. Then that surface(s) is described by some equation (or set of equations and associated parameters). can we specialized (i.e. modify) the NS equations for those arbitrary surface parameters. WE may still need to solve them numerically but can we at least incorporate complicated geometric information directly in NS equations (not talking about boundary conditions). Furthermore can we manipulate those resulting equations so that we can have expressions for aerodynamic forces or moments directly in terms of those surface parameters. IF we did, we would have then a unified theory of aerodynamics for arbitrary set of surfaces put together (say as an aircraft). WE could tweak those parameters and directly optimize geometry. A theory that allows us to calculate forces and moments directly (rather then find say pressure or velocity distributions from solutions of Navier stokes equations based on a given geometry and boundary conditions). What I meant was we don't have such an aerodynamics theory. That's sad as it means country like ours needs billions of dollars to develop an aircraft despite having very good engineers. Other than aerodynamics, similar problem crop up in other fields.

Also I was NOT at all implying that you can't explain in easy terms. I myself probably can't. I have not even read your posts at that time. I was saying it all can be quite complex for the new comer and they may find it hard even with the best of explanation. This is also true when studying for undergraduate studies. So you should continue as it will help people in the long run. Also personally I realized such interaction have added to my own understanding much more than silent readings at times.

I mean come on, it may occurs to many not involved in engineering, hearing after a Pakistani missile test, " all parameters have been validated successfully", that what are these mysterious parameters.

So I was explaining (or confusing perhaps) other readers (other than you I mean) that we get estimates of say aerodynamics parameters from wind tunnels (or CFD) and then flight test to see those parameters values are actually same as the one estimated on the ground in the wind tunnels. That's validates them for that particular batch of missiles (Or we need to update them with more accurate ones so estimate them directly using actual flight tests).

That those aerodynamic parameters let us things such as say how changes in fin angle on a missile will effect its behavior. this way may be some teenager will get one thing or two or at least would know that it is not all that mysterious. Demystified, they might even chose engineering as a profession and we need technical professional in Pakistan.

SO reading your post, I genuinely believe that you can explain in much more concrete and easier terms. I can't explain that well. May be I was unconsciously projecting my own inability on you in an indirect way. Though I never meant it. It happens. What we can't do, we presume, unintentionally that others can't do either. It normal human reactions. I myself can't explain well at times so I was seeing myself I guess.

Whenever I am free, I will definitely visit this forum and share my vies. But please do note for future reference, a lot of explanations are for other readers. They may read our replies to each other.

WE will definitely have more chats in the future, Insha-Allah. But do note once again that my explanations (no matter how bad ) are meant for others who might also end up reading the post, even when you are being addressed.

Brother, if your audience was other people than definitely most of them won't get.
Furthermore, NSE equations are not specialised for aerodynamics... but these are general flow equations and can be applied to any Newtonian fluids in the continuum ...for non-Newtonian fluids the viscosity terms in RHS are modified to incorporate the shear rate dependence instead of the dynamic.
By the way, the most accurate approach is DNS but it requires huge amount of computational power and has only be used for very small domains and very low Re flows. But you get huge resolution. To reduce the computational cost, we use CFD which is quite good in many cases...depending on the resolution of the grid and convergence criteria but it is not as accurate as DNS so a nice compromise is the LES or DES. But those require experienced people.

Special cases of NEs are Euler equations and what we numerically solve in CFD is the RANS equations...I can go on and on but do you really think will help them. What we need is make it simple and built upon it, instead of scare away people through complicated esoteric terms and jargon.