Computational Science Stack Exchange
Computational Science Stack Exchange

Questions tagged [fluid-dynamics]

The study of the properties of fluids and gases in motion

636 questions
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Disadvantages of common discretization schemes for CFD simulations

The other day, my computational fluid dynamics instructor was absent and he sent in his PhD candidate to substitute for him. In the lecture he gave, he seemed to indicate several disadvantages associated with various discretization schemes for…
Paul
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CFD: Does order of time stepping scheme affect steady state solution? If yes why?

I am trying to solve Ideal MHD equation using semi discrete methods, ENO spatial reconstructions and TVD RK time stepping. I am getting different steady state solutions with different temporal order. Is it correct?
0b1100001
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Dirichlet-Neumann boundary condition solution becomes unstable - Pressure Correction Method

I am simulating incompressible flow over a cylinder at Reynold number of 500. I am solving navier stokes equation using pressure correction method. My solution becomes unstable after certain time (approximately 5s). I have tried refining my mesh,…
illusion
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Can compressible flow solvers be used to solve incompressible flow?

I know that incompressible and compressible flow solvers are specifically designed to solve different types of problems with different fluid properties/flow conditions. Clearly, among the advantages of using incompressible flow solvers for modeling…
Paul
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Definition of incompressible flow

As all knows incompressible flow doesn't exist in reality, its an assumption introduced to simplify governing equations. We can not apply this assumption straightforward. Generally Mach number(M<0.3 for incompressible flow), density variation(zero…
Shri
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What is the simplest method for solving incompressible Navier-Stokes equations?

By "the simplest" I mean the simplest to learn and implement from scratch. I hope my question can more or less be answered.
vehsakul
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Euler equations in 2d

As an assignment in college, I did a 1d simulation. The problem statement was to solve 1d shock tube problem involving compressible ideal gas as working fluid. For this problem, I solved system of Eulers equations using Roe's Riemann solver. I want…
Subodh
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Importance of the Time Step Value for the Accuracy of a Transient CFD Simulation

Overview My understanding is that one should use a time step $\Delta t < \frac{h}{v}$ (where h - smallest mesh element, v - velocity) to get an accurate result. But how important is this really for the accuracy of the simulation? Is it as important…
A.L. Verminburger
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Are there any general fluid dynamics frameworks?

Are there any frameworks that could be classified as "general computational fluid dynamics framework"? What I'm thinking of is a framework that's modular and extensible in order to allow the development of new algorithms pretty much unlimitedly. And…
mavavilj
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beginning Computational Fluid Dynamics

I am starting a self study course in computational fluid dynamics. I use ( An introduction to computational fluid dynamics : the finite volume method) I am learning Python programming language. The problem is that I cannot understand most things in…
Mohammed Attya
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Flow past a cylinder - Projection Method - Boundary Conditions

I plan to write a code that solves the flow past a cylinder and try to see the Von-Karman vortex street. I will solve the 2-D viscous, incompressible Navier-Stokes using the projection method. The following figure demonstrates a subset of my…
l3win
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Which tool/metric do you recommend to evaluate the quality and validity of a Large Eddy Simulation?

The idea behind Large Eddy Simulation is to solve explicitely the scales of the flow that are resolved by the computational grid and to model the sub-grid scales. Ideally, the cut-off between these scales is located in the inertial range of the…
FrenchKheldar
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CFD for high-detailed turbulence and non-linear waves

What are typical (or promising) techniques and methods in CFD to achieve high-detailed turbulence and non-linear waves interaction? And with "active" geometry (when bodies interacts with fluid in both ways)? Currently I've been recommended SPH, but…
Mixo123
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What makes turbomachinery so special in CFD

As my experience with CFD grows, I start to gain the feeling that turbomacinery is kind of special in CFD: there are special tools tailor for it. For example, ANSYS has TurboGrid or Vista TF for turbomachinery design. And OpenFOAM has special…
Taozi
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Why does the wrong mesh scale produce a more accurate result?

I am using an Euler-Euler method to model two phases - both are treated as a continuum using modified Navier-Stokes equations. One phase is air and the other is particles, that are being entrained by the air. The original geometry is very small, the…
A.L. Verminburger
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