Actual fluid mechanics used in CFD?

In summary, Don't be so sure that you don't like "all that shock stuff". You may not have liked it initially because it is conceptually difficult. Once you play around with it a little more, and you have a better understanding you may actually like it more than the other stuff.
  • #1
creepypasta13
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I just recently graduated with my BS degrees in physics and applied math but am interested in switching my career path towards mechanical engineering. I honestly don't know much about CFD at all, so I was wondering how much of the fluid mechanics you learn in the ME classes is actually used in CFD for the graduate-level courses, and for actual engineers who use CFD on their job. I've taken one quarter of fluid mechanics in the ME dept and I enjoyed the entire course (we skipped the section covering Navier-Stokes, vorticity, etc) until the very end when we covered shock waves, sonic/subsonic/supersonic flows, isentropic flows, etc. But since I enjoyed mechanics, statics, and numerical analysis/modeling/simulation instead of experimental work, I heard that computational mechanics and CFD were good fits for me. Also, I want to apply my knowledge to work with tanks, missiles, and weapons systems. Since I didn't like the part of my fluid mech class that covered shock waves, does that mean I won't like doing CFD? how much of that is used in CFD?

also, one last question I have is just a general question about ME: If I want to find a position in industry doing modeling/simulation work instead of experimental and hands-on work, do I need to do the thesis-option for my MSME? or can I find such positions with just the coursework-only MSME?
 
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  • #2
  1. There are plenty of incompressible (i.e. no shocks) fluid mechanical problems that CFD is used for solving in industry. However, a lot of times a finite difference code will actually treat the material as slightly compressible for numerical stability reasons. In these cases compressible knowledge (speed of sound and shocks and stuff) actually helps you interpret and troubleshoot CFD problems for incompressible systems.
  2. Don't be so sure that you don't like "all that shock stuff". You may not have liked it initially because it is conceptually difficult. Once you play around with it a little more, and you have a better understanding you may actually like it more than the other stuff.
  3. If you want to do any kind of computational mechanics in industry you'll probably need/want at least a masters degree, if not a PhD.
  4. Definitely do a thesis for your masters. It is an excellent opportunity for you to explore an area in moderate depth and develop your skills as an engineer.
  5. In general if you want to work on tanks and missiles you're probably going to have to be a citizen of whatever country you're working in. That said, why do you want to hurt people? Use you're powers for good.
 
  • #3
freireib said:
  1. Don't be so sure that you don't like "all that shock stuff". You may not have liked it initially because it is conceptually difficult. Once you play around with it a little more, and you have a better understanding you may actually like it more than the other stuff.
  2. If you want to do any kind of computational mechanics in industry you'll probably need/want at least a masters degree, if not a PhD.
  3. Definitely do a thesis for your masters. It is an excellent opportunity for you to explore an area in moderate depth and develop your skills as an engineer.
  4. In general if you want to work on tanks and missiles you're probably going to have to be a citizen of whatever country you're working in. That said, why do you want to hurt people? Use you're powers for good.

Thanks for the response. well at my school not many profs want to fund MS students, as they will reserve it only for phD students, so that was one reason why I thought about just doing the coursework-only MS, instead of the thesis option.
 
  • #4
Apply to a school that is strong in CFD and would be willing to fund you. Stanford is good at CFD.
 
  • #5
CFD is just a mathematical tool used to solve fluid problems. What's important is that you have a solid foundation of knowledge in fluid dynamics, and it sounds like you have that.
 
  • #6
Brian_C said:
CFD is just a mathematical tool used to solve fluid problems. What's important is that you have a solid foundation of knowledge in fluid dynamics, and it sounds like you have that.

well I didn't even know I would like CFD or advanced fluid mechanics since I didn't like the part of my intro to fluid mechanics course that covered compressible flows. I don't know if only one quarter of fluid mechanics considered as a solid foundation
 
  • #7
Cyrus said:
Apply to a school that is strong in CFD and would be willing to fund you. Stanford is good at CFD.

I wish it were that easy. I missed the deadline for all the other grad schools except my own, since at the time I didn't want to apply to grad schools. So I could accept my school's offer and start this fall but few professors do research that seems interesting and few are willing to fund MS students. Or I could wait another year to apply to other schools, but I want to start my MS ASAP
 
  • #8
creepypasta13 said:
I wish it were that easy. I missed the deadline for all the other grad schools except my own, since at the time I didn't want to apply to grad schools. So I could accept my school's offer and start this fall but few professors do research that seems interesting and few are willing to fund MS students. Or I could wait another year to apply to other schools, but I want to start my MS ASAP

Well, what is more important in the long run. Getting an MS degree ASAP, or going to a good school and being funded to do CFD?

Also, you have a degree in physics and math. You should be able to pick up a book (Perhaps, Anderson's Fundamentals of Aerodynamics) and read it cover to cover on your own as you wait for the new deadlines to other grad schools. You can also read Anderson's CFD book.
 
  • #9
After auditing a course in aerodynamics for a couple weeks so far, it seems pretty interesting and something I would like. But we haven't covered compressible flows yet. I also did some more research into a career in engineering and it seems that a lot of engineers don't like their jobs.

I heard that engineers don't recommend others to pursue an engineering career because they don't like their jobs and the pay isn't great, and also because engineering doesn't have very strong job security and over-specialization. Also, I heard that outsourcing will just continue to become a major problem, particularly in a modeling/simulation area such as CFD, which is especially troubling to me. Do you guys agree with what I said?

Do you guys think those with MS degrees in Computational Science and Engineering have better job opportunities than pure engineering degrees? So would a CFD in applied math open more doors than a CFD in ME? Another engineer I heard even mentioned that overspecialization is such a problem that one would have better job opportunities with a physics than engineering degree
 
  • #10
Outsourcing may or may not be a problem - it really depends on many factors like who you work with and what projects you are doing.

Job security is a function of many things. In the industry, it is mostly expected that you grow into someone who brings in projects and money for the company. Degrees will only take you so far.
 
  • #11
Not considering the employment factor, I'm still not sure whether to get my MS/phD in applied math vs ME/AE. It's hard for me to make that decision since I haven't taken an advanced fluids class. But I did audit an aerodynamics class for a few weeks. I loved the theory, derivations and mathematics involving vorticity, stream function, velocity potential, and Laplace's equation. I also really liked my heat transfer class. But I haven't taken propulsion, which looks difficult since I had lots of trouble with my thermo class. So maybe an applied math program in CFD is a better fit for me?
 

Related to Actual fluid mechanics used in CFD?

1. What is the difference between laminar and turbulent flow in CFD?

Laminar flow is characterized by smooth and predictable motion of the fluid particles, while turbulent flow is characterized by chaotic and unpredictable motion. In CFD, laminar flow is often used in simpler simulations, while turbulent flow is used in more complex simulations that involve interactions between different fluid layers.

2. How is turbulence modeled in CFD simulations?

Turbulence is modeled in CFD simulations using various turbulence models such as the Reynolds-Averaged Navier-Stokes (RANS) equations or the Large Eddy Simulation (LES) approach. These models use mathematical equations to simulate the turbulent behavior of fluids and provide more accurate results compared to assuming laminar flow.

3. What is the role of boundary conditions in CFD simulations?

Boundary conditions are essential in CFD simulations as they define the behavior of the fluid at the edges of the computational domain. These conditions include the velocity, pressure, and temperature of the fluid at the boundaries, which help to accurately simulate the flow behavior and interactions with solid surfaces.

4. How are discretization methods used in CFD simulations?

Discretization methods are used to divide the continuous fluid domain into smaller elements, allowing for the use of numerical methods to solve the governing equations. The most commonly used discretization methods in CFD are the Finite Volume Method (FVM) and Finite Difference Method (FDM), which divide the domain into cells or control volumes and approximate the equations at each location.

5. What are the main challenges in CFD simulations of real-world fluid mechanics problems?

Some of the main challenges in CFD simulations of real-world fluid mechanics problems include accurately modeling complex geometries, handling multiphase flows, and dealing with the high computational cost of simulations. Other challenges include accounting for turbulence, correctly modeling boundary conditions, and validating the results with experimental data.

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