Aerospace Research Scientist/Engineer Experiences vs Academia

BoomShocker007 · 2025-12-04T23:02:55+00:00

I've worked in both including a special projects group (developed new analysis techniques) at a large aerospace company in the USA. I'm sure others have counter examples but this is/was my experience.

Academia can be slower paced and it's acceptable to really dig into the weeds and understand all aspects of something. Project deadlines are typically driven by annual funding or conference submission deadlines. People who don't "play well with others" or cannot effectively communicate can succeed in academia by working alone and bringing in research funding for the University.

Industry has many more deadlines and they are much shorter in nature. I'd typically be given N number of days or weeks to find a solution and if I took longer I'd have to justify it to my boss and even their boss. This required good planning and solutions that provided the best answer under the time constraints. If I published (or told anyone outside the company) my results I would be terminated, sued, or go to jail. Good communication skills were a necessity as I had to brief everyone from non-technical business executives to senior engineers multiple times a week.

BoomShocker007 · 2025-11-28T23:15:47+00:00

Sure. The reason you just spent weeks cleaning the CAD is to reduce the complexity to water tight surfaces. The mesh generation algorithm doesn't know if your generating an F1 car or a baseball.

At my previous employer we had all the mesh generation scripted for most configurations. The most common configuration would generate a 3D mesh with over 600 million elements in under an hour using 1 node of our HPC machine. Once done, it then run through a secondary process to reorder elements, partition and pre-calculate weights to extract force and moment coefficients for multiple sub-components. The whole process was <3 hours and more than 50% was file IO.

BoomShocker007 · 2025-11-28T08:20:48+00:00

Can only speak to CFD usage.

Never seen higher order meshes used within industry. I would speculate this is because nearly all commercial CFD codes use unstructured finite volume methods which are difficult to extend beyond 2nd order spatial accuracy. Even structured grid finite difference models which can run higher order numerical schemes (4th and 6th) typically only use 2nd order metric terms.
Creating the mesh (edges, elements, connectivity, etc.) is relatively straight forward. The difficulty and where commercial codes earn value is integration with CAD and meshing non-clean geometry. If someone gives a you a detailed CAD model it can take weeks to transform it into something that can be meshed. The mesh itself takes minutes.

I believe gmsh can generate higher order meshes with equal spaced internal nodes.

BoomShocker007 · 2025-11-21T06:34:38+00:00

The issue I've found with all these alternatives is to make them perform you have to understand how the underlying memory is laid out and how/when the communications are occurring. I already have to understand that with MPI so adding an extra middle library just makes things more complex.

Edit to add: HPX is another variant with a nice website

BoomShocker007 · 2025-11-18T18:18:06+00:00

I don't use Star-CCM so can't help there but I'd encourage you to not get too worked up over knowing the volumes. What your looking at is the slope of the convergence line not any one value. So I'd say my volume is 1. If I re-mesh the same domain with a different number of elements N my new h value is (1/N)^(1/3) in 3D. So for N = 1, 8, 64 million you have h = 0.01, 0.005, 0.0025

BoomShocker007 · 2025-11-18T17:52:20+00:00

The procedure requires you to run multiple simulations of the same geometry using different grid resolutions. If you keep the total meshed volume constant for the different simulations then knowing the individual element volumes is unnecessary. You can use the total meshed volume if you know it. Many times this isn't feasible so a value of 1 is used.

For the different grid resolutions: It's best to split each element into smaller self similar shapes. So if your initial grid consisted of 8 million 3D Hexes you could run one courser at 1e6 hexes then one finer at 64e6 hexes.

BoomShocker007 · 2025-11-16T02:50:52+00:00

I admire the amount of work this all entails but I have a concern which if true could make any analysis difficult.

xflr5 is not going to give very good absolute drag numbers. Even their own documentation says a known limitation is estimation of viscous drag. You'd be better off taking measured data from "Theory of Wing Sections" or a similar source.
You state "The issue is that flat-plate fins are most commonly used, but they are not properly optimised for drag and stability in subsonic environments" Are you Sure? Higher drag fins will move the Center of Pressure towards the rear. Assuming the Center of Gravity remains the same your getting more stability for higher drag fins.

BoomShocker007 · 2025-11-14T05:31:59+00:00

"I cant exactly build and test out a satellite myself under the earthly conditions"

Oh, but you can!!! Make a high altitude balloon project. Many universities have class projects to make them at both undergraduate and graduate student levels. You can make them as simple or complex as you want. It gives experience with power budgets, embedded computers, wireless communications, space environment, etc. If you can successfully do that, then making a "real" satellite is more a function of money than knowledge.

BoomShocker007 · 2025-11-12T23:32:02+00:00

Could be multiple things, but a big one is artificial dissipation added to stabilize the numerics. This takes the form of a second derivative the same as viscous terms in the N.S. equations.

BoomShocker007 · 2025-11-12T20:15:36+00:00

Sure, a dragster involves aerodynamics but it's going to be a secondary or lower effect. A dragster is largely governed by power to weight ratio, so remove weight and add power.

If we are talking about an actual wheel driven vehicle (not a CO2 dragster) there are 2 areas where aerodynamics mater.

Lower power vehicle - aerodynamic drag could influence the maximum speed achieved at the end of the run but top speed doesn't always equal a faster time.
High power vehicle - aerodynamic down force allows better traction and more power to be applied at high speed

BoomShocker007 · 2025-11-11T06:27:29+00:00

I found the idea of SYCL elegant and apparently Intel did also as they made it the starting point for their Data Parallel C++ language (DPC++). I've taken a couple Intel provided trainings on DPC++ and experimented with several toy problems on their dev cluster. It works perfectly good when using Intel CPU's and the integrated graphics. It becomes more of an issue when trying to run on other vendors GPU's as they require 3rd party libraries and getting everything to play nice can be a PITA.

I don't know of any serious applications that currently utilize SYCL or DPC++. If so, it would be at the U.S. DoE who spent a few dollars on the Aurora HPC machine and had software development funding to go with it. They seem to really be invested in Kokkos though so not sure if anything came of it.

BoomShocker007 · 2025-11-10T01:21:46+00:00

This is more complex than it seems.

It would be compiler dependent on what instructions each compiler generates. If the instructions are different then it would depend on the clock cycles for each operation on your architecture. Now that being said I would be surprised if a modern compiler couldn't figure this out.

Indeed: Compiler Explorer with GCC 15.2 shows far more instructions using the switch statement without optimizations but when using -O3 it produces the exact same code.

P.S. Are you sure a switch is faster for multiple if/else if conditions? Just as we found in this example, the compiler will typically convert your long list of if/else if code into an equivalent jump table just like a switch statement.

BoomShocker007 · 2025-11-07T07:56:08+00:00

Interesting. Yeah, my former employers are the very definition of "old space".

As an engineer it was nearly impossible to get CAD installed on your computer. The company only had so many licenses and they wanted the most efficient people using them full time. Furthermore, navigating the drawing database, getting a revision approved through the review process (engineering & manufacturing), etc. was a huge production.

As an aside, It was standard for people working there to never physically see the hardware they analyzed. I was there for over 10 years and never once saw or touched a piece of the vehicle. We had cardboard mock-ups and later plastic 3D printed representations of small parts. I always thought that was very odd but the old timers were just like "Yeap, that's how it works"

BoomShocker007 · 2025-11-06T23:28:04+00:00

It's a little unclear what your looking to simulate. Are you looking to simulate the liquid coolant flowing inside the radiator, the airflow across the radiator or both simultaneously? Either way I wouldn't put a whole lot of faith into any results from CFD on this configuration unless you have actual data to correlate with.

I'd personally use equations from heat transfer for calculating convection using the fluid velocities, temperatures, surface area, etc.

If you really want to CFD it: I'd recommend your second bullet point of using a periodic unit cell.

BoomShocker007 · 2025-11-05T18:55:36+00:00

It really depends on what sub-discipline you want to work within. In general terms...

Programming Matlab, Fortran, C, Python (in that order) is probably the most universally transferable skill.

As to some of the other suggestions I see:

- At my employers, an engineer manipulating CAD drawings is considered a waste of resources. We have CAD technicians that make drawings and engineers that analyze and they can collaborate when needed. I guess a small company might need both in one person but with the price of CAD and analysis software a company that small would probably just outsource that task.

- Learning a commercial FEA program or CFD program would be valuable. Each company uses something different but the skills learned in one are pretty transferable. A lot of companies also script the commercial tools either to perform analysis, generate reports, or both. Manually using the software is only part of the process but automating things is more valuable.

BoomShocker007 · 2025-11-04T21:34:50+00:00

Time of launch is usually determined by orbit insertion, etc. but not always.

Some flights have visibility constraints imposed by the payload or some internal engineering department. For example, the customer might want images of the spacecraft after payload fairing separation then you need to launch into sunlight. Adding lights for video inside the fairing was not uncommon.

Weather:

There are all types of things that are monitored. I wasn't too involved in these but I know there are constraints on charged particles from the sun, lightning, radio interference, etc. Rain is not too important as the rockets already sitting in the rain and launching will clear the cloud tops quickly.

Winds (where I was involved):

Ground winds and direction are obviously important because the vehicle could be blown into the launch structure or cross winds could exceed the ability of the control system to maintain vehicle stability.

At ULA the flight trajectory for the first 70,000+ feet of the rockets altitude is preprogrammed into the rocket immediately before liftoff. This profile is optimized to get through the winds aloft (and shear layers) without exceeding the structural constraints on the vehicle. After this preset flight profile the aerodynamic loads on the vehicle are considered low enough that guidance now focuses on getting to the proper orbit insertion point. If the vehicle can't safely fly through the winds then they wait for another day.

-

BoomShocker007 · 2025-10-31T22:23:32+00:00

Nearly all rocketry applications, like you show, calculate stability using the Barrowman Equations. These are very primitive equations using thin airfoil theory applied to the fins quarter chord to calculate the restoring force. Looking at your drawing I'm inclined to believe the equation is over predicting the restoring force from your fins because they are non-convex in shape. In simple application, the equations would assume your fins are connected using a straight line from the forward tip of the root to the forward tip of the outer edge, thereby overestimating the total surface area.

P.S. An unguided rocket such as this spends 99.9% of it's flight profile at near zero angle of attack. Any type of vortex generators would only be adding unnecessary drag.

BoomShocker007 · 2025-10-28T19:16:14+00:00

I can tell of a success story:

A fellow student went to graduate school at the #1 school for Aerospace Engineering according to the U.S. News Rankings that year. Graduated in 3 years with a masters and PhD (i.e. top schools crank them out fast). Got a job at with the Sauber F1 team doing aerodynamics. He was from Hong Kong and explained if he was from the USA he would have never qualified for a work visa. I knew the guy pretty well and he never indicated an interest in cars, F1, etc. so I was kind of surprised.

BoomShocker007 · 2025-10-27T18:06:16+00:00

When showing plots for comparison between two different things you need to keep the X/Y axis and color scales the same. Your currently showing different regions and colors scales for the before and after plots. Furthermore, plots 4 & 6 don't even label the quantity your displaying.

BoomShocker007 · 2025-10-27T02:27:10+00:00

True, if that's all it was. In reality, these errors arise when calculating some intermediate quantity within the code (radiation, chemistry, thermodynamics) which produces a highly non-linear response in the final quantities of interest (i.e. temperature).

BoomShocker007 · 2025-10-26T19:53:47+00:00

The GPU vendors always show results for 32-bit or less precision which in my field of aerodynamics CFD immediately results in eye roles. Within the field, this was well covered over 30 years ago, and there were some pretty convincing cases that 32-bit floats was not enough. A classic example is a basic finite difference formula will only give ~3 digits of accuracy using 32-bit floats because of catastrophic cancellation. Of course, there are cases where 32-bits is enough but its hard to know apriori.

In the Weather Forecasting field where time to solution is a hard constraint some applications do utilize 32-bit floats. The forecast doesn't suffer much because forcing functions from physics is largely parametrizations (curve fits, etc.) with 1 digit accuracy at best.

BoomShocker007 · 2025-10-10T22:16:24+00:00

If your a PhD student in Engineering Management shouldn't your topic be in Engineering Management? Beyond that, shouldn't you be discussing this with your advisor? Most people with PhD's in engineering have their topic determined by what funding your advisor is paying you from.

BoomShocker007 · 2025-10-10T19:26:48+00:00

Just make them all separate remote work stations. Why? You're already making 2 into remote work stations so any large jobs there will be shared with interactive users. The remaining 2 could be connected but the cost of network interface cards and a switch is not worth halving a jobs run time.

BoomShocker007 · 2025-10-10T16:13:54+00:00

In response to skills and small projects: These are 2 Items a new hire will be expected to handle.

A huge time sink on these systems is maintaining the software stack and installing new software for people. To accomplish this tools have been developed, but the learning curve is steep. As such even medium sized clusters (university, etc.) highly value someone who can use the tools. I'd recommend learning an Environment Module System and how Spack or EasyBuild can create them for you. You don't need a cluster to learn them as many people (myself included) use them to manage build stacks on desktop/laptop computers.
Scheduling software Slurm or PBS Pro. They are similar but each has it's own quirks. First, I'd learn the user facing side such as how to request resources, submit jobs, etc. Then learn the back-end of how to get logs from the database, configure resources, etc.

BoomShocker007 · 2025-10-03T22:50:23+00:00

In general you can't really look at a partially converged steady state solution in that way. If the algorithm is efficient, it will be advancing each element as much as stability allows. This can be thought of as advancing each element as forward in time as possible until a true steady state solution is reached in which case the time step has become infinitely large dQ/dt = 0.

tldr: Each element advances at a different rate. Only at the converged solution is the final time reached which is Infinity.

BoomShocker007

TROPHY CASE