# Cfd Definition and 35 Discussions

Computational fluid dynamics (CFD) are used to understand complex thermal flow regimes in power plants. The thermal power plant may be divided into different subsectors and the CFD analysis applied to critical equipment/components - mainly different types of heat exchangers - which are of crucial significance for efficient and trouble free long-term operation of the plant.

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1. ### I Flow rate calculation of coating application

Dear all, I'm currently working on a basic coating application and I'm struggling to get the flow rate stable. I'm trying to figure out how to calculate the theoretical flow rate in the application. The coating is stored in a pressure tank, which we put on an overpressure of 15psi. From the...
2. ### Modelling of two phase flow in packed bed (continued)

Previous post linked here, where a model for the two phase flow of air through a packed bed was developed: https://www.physicsforums.com/threads/modelling-of-two-phase-flow-in-packed-bed-using-conservation-equations.1008754/ The first few comments on this new thread will be copies of the...
3. ### Modelling of two phase flow in packed bed using conservation equations

Previously, I have seen the derivation of the energy conservation equations for simulation of single phase flow in a porous media (a packed bed). These are the energy equations for the solid and fluid respectively: I understand the derivation, however, these equations will only work when the...
4. ### Typical surface roughness heights for aircraft surfaces

Hello! I am investigating some preliminary aerodynamics on a regional turboprop and for the drag model the surface roughness height of the airplane is required as an input. For this i do not have any data. In which range are the typical values for modern aircraft surfaces? Thanks a lot!
5. ### Counterfactual Definiteness and MWI in Wiki

Summary: Counterfactual Definitiveness and Many World's Interpretation Sorry for all these threads, my noetic fluids and bursting. Wiki states the following: In quantum mechanics, counterfactual definiteness (CFD) is the ability to speak "meaningfully" of the definiteness of the results of...
6. ### Ridiculously low drag coefficient from OpenFOAM CFD

(New thread following up to a conversation in another thread). I'm using SimFlow 3.1 with OpenFOAM 5 on Linux to try to evaluate the drag coefficient of a water rocket body, constructed from a 2-liter Coke bottle with a conical nose, traveling through air at 77 m/s. This should be a simple...
7. ### Navier-Stokes Equations - Numberphile

Tom Crawford (sporting a Navier-Stokes tattoo) talks about the famed equations - subject of a \$1m Millennium Prize.

18. ### Courses Is CFD fluid mechanics + computer science?

I'm having fluid dynamics classes right now and I'm enjoying it very much (much more than my solid mechanics classes, by the way). Also, I do like programming and computer science, and CFD looks like a very interesting field. I'm developing a real interest for it. One question for those who are...
19. ### Engineering Opening a CFD consulting firm?

I've been thinking about entrepreneurship in the engineering field. Unlike other fields like computer science, where small companies with small investments often end up becoming huge business, engineering is usually a very expensive thing. So consulting is a way for those who don't want to work...

I simulated an incompressible turbulent flow across a tube. I managed to solve it using OpenFoam and the results seem to be right. However, I noted some vacuum pressure after the sudden expansion but can't figure out why the pressure decreases and then increases again. According to Bernoulli's...
21. ### A How to solve (or close) the incompressible Navier-Stokes flow eqs for a compressible fluid?

I did a lot of googling but could not find a satisfying answer to my question, hence a post here. Question: How to solve (or close) the isothermal incompressible Navier-Stokes equations for an isothermal compressible fluid? Situation: We have a compressible fluid, for example a gas. The flow...
22. ### A FEM for solving PDEs

Hi, my background is in mathematics, and theoretical physics. I am new to the realm of solving PDEs using Finite element methods, does anyone know of any good introductory level textbooks for course notes? I had a poke around online and couldn't find anything overly useful. Also I am...
23. ### Guidance or tutorial of applying pseudo-material method

Hi, I'm working on a project of coupled simulation involving MCNP and Fluent, and having trouble with how to apply the pseudo-material method in cross section handling. Is there any related material or tutorial? Or, does anyone know the procedure of applying the method and what kind of files the...

I'm looking for an example of CFD analysis on a pressure reducing regulator. I think may be fairly complicated because the main valve position is not fixed but rather controlled by the pressure differential acting across the valve, the main valve spring, and the load spring minus the pressure...
25. ### Python Doublet + Uniform Flow // Streamfunction Polar Plot Help

Hello, Python,CFD and PF newbie here. I am using Spyder (Python 3.5) and I managed to plot my streamfunction in cartesian coordinates. I tried transforming and plotting in polar coordinates but I am not sure that what i have done is correct. I am not even sure what the plot should look like :/...
26. ### Polyflow terms

What is the "plane of symmetry", "zero velocity wall" and "free surface" terms which I have seen in Polyflow? It says in Vnormal=Fs=0 for plane of symmetry and Vnormal= Vs= 0 for zero velocity Wall. Now I get when Vs=Vn=0 it means that the wall isn't moving and it's in a static state but didnt...
27. ### Fluid solid interaction boundary condition problem

I have come across the paper attached in which a 1D fluid piston is modeled. I have question on the boundary conditions (BCs) of the system. Essentially, the problem consists of a fluid chamber in contact with a spring (a mass -spring system). ALE is used to move the mesh. I am not certain...
28. ### Relation between energy conservation and numerical stability

Hi, Consider the conservation laws for an isothermal linear incompressible flow governed by the mass and momentum equation. The kinetic energy equation is then solved to see if energy conserved. Can anyone tell me if once it is shown energy is conserved, it implies that convergence is obtained...
29. ### CFD Thermodynamics flow in Angular momentum system

Angular momentum is conserved in a closed system. Is thermal isolation required too? An example special case in mind is a closed cavity high speed rotation. It contains high pressure gas and the thermal flow is driving convection currents creating turbulence and or a heat pumping loop...
30. ### ANSYS Mesher face views

Homework Statement I have a part in my ANSYS Mesher that I am attempting to mesh Homework Equations I need to view the interior of my part as seen in the photo. However, each time I try to view my mesh this way, I get the view seen in the second image. I need to fix this issue so that I can...
31. ### Turbulence viscocity

whats turbulent viscocity?How it different from viscocity?Also i read that viscocity is fluid property.So has flow condition like laminar or turbulent has any effect on viscocity?
32. ### Engineering Nuclear Engineering vs Mechanical Engineering

I have a bachelor degree in Mechanical Engineering and I am interested in CFD. I have an admit offer for MS in Nuclear Engineering at UIUC with RA and MS in Mechanical Engineering at Stanford without any assistantship. Which one is a better option to choose considering the fact that I am not a...
33. ### Comparison between CFD results and experimental data

Hi everybody, my question is not properly about CFD but mainly about Fluid Dynamics itself. I have performed a RANS simulation of a round jet of methane and air and now I'd like to compare those results to some experiments. Unfortunately there aren't papers about experimental data for...
34. ### Can applied physicists be CFD analysts

I am about to graduate with an aerospace engineering degree. I am planning to go into grad school for Applied physics(probably plasma physics), which I find very interesting. But the main reason I joined the aerospace degree was because I was interested in CFD. But since I could't land any...
35. ### CFD:Symmetry in Lagrangian

Hi guys, have a very tricky question on my HW to find compact group of global symmetry to this Lagrangian of 2 complex scalar fields L={\partial_\mu \phi_1^*}{\partial_\mu \phi_1}+{\partial_\mu \phi_2^*}{\partial_\mu \phi_2}-\lambda(\phi_1^* \phi_1 - \phi_2^* \phi_2 - v^2)^2 and I can't figure...