# Questions tagged [fluid-dynamics]

The study of the properties of fluids and gases in motion

423 questions
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### GPU-enabled Lattice Boltzmann solvers?

Is anybody aware of any GPU-enabled Lattice Boltzmann solvers (preferably on C++/OpenCL and open-source) that would be recommended? I have found Advanced Simulation Library, but it seems to be very ...
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### How to deal with nonlinear term in Navier Stokes equations (finite element code)

I am trying to solve the Navier Stokes equations using the finite element method. I plan on using the pressure correction method to deal with the pressure and an implicit time stepping scheme for ...
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### Adaptive mesh refinement basic conceptual problem

I am a beginner in adaptive mesh refinement (AMR). After I am done with the first two papers by Dr. Marsha Berger, I was trying to write my own code for a problem which has a parabolic partial ...
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### Representation of polynomial order in CFD codes

I am currently working on a CFD code over a cubic grid. Now, the number of elements used in the simulation is decomposed among the number of processors. Each of those processors (a section of the cube)...
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### Why are upwind schemes stable in convection flow calculation?

It is well known that upwind schemes are stable when calculating convection flows with $|\text{Pe}|>2$, $\text{Pe}$ is the Peclet number. Why is that, and why is central difference unstable? Is ...
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### A Question About the Rhie-Chow Interpolation Used for Solving the Incompressible Navier-Stokes Equations on Unstructured Grids

When using the SIMPLE method on a mesh with a collocated variable arrangement, the following interpolation is used for the advecting velocities: u_f = \overline{u}_f - \overline{D}_f\...
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### Direct Numerical Simulation of reacting flows

I need to write a DNS code for simulating reacting flows in turbulent conditions. The code has to be highly scalable, because the computational cost of simulations is expected very large. My idea is ...
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### 2D Poisson Solver for Taylor Green Vortex Problem

I am trying to write a 2D Navier Stokes solver using an RK3 for time advancement in python. For debugging, I have converted the RK3 to an Euler step for simplicity. Checking my divergence for my ...
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### applications of computational geometry in fields such as CFD?

Out of curiosity, I was recently trying to search what skills are required to be successful as developer in scientific computing field (e.g. CFD or similar). And to do so, I was going to through ...
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### alternatives to moving mesh technique

If one has to simulate oscillating plate/solid wall ( sinusoidal function of time) in a domain (a simple piston movement in 'y' direction), the obvious way would be scenario 1. For brevity, assume ...
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### 2D Stokes equation Code

Does anyone know where could I find a code (in Matlab or Mathematica, for example) for he Stokes equation in 2D? It has been solved numerically by so many people and referenced in so many paper that I ...
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### Add User-defined/custom differential equations in OpenFoam (CFD)

I am new to OpenFoam. And I am trying to add a set (user defined) of differential equations to OpenFoam. I want to solve this user defined set of equations at each time point in addition to standard ...
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### Help about Fluid-Fluid coupling techniques

I need a little help and advice with a project I want to do: the idea is to "couple" (I don't know whether I can call it like this) a conservative Navier-Stokes Solver (Fractional-step, 2nd order FDM) ...
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### The “standard map” and Jupiter's red spot [closed]

Has there been an attempt to "explain" Jupiter's Red Spot via what is known as the standard map in chaos theory? I cannot be the first to notice the visual similarities...       &...
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### How to interpret/convert density in 2D simulations?

Density has units of $kg/m^3$. In simulations often scaling is done to deal with non-dimensional values, so the physical density is converted to the non-dimensional density so that it can be used in ...
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### Value of density when there are no or very few neighbours in SPH simulation

Sorry for the noob question. I am trying to implement SPH using the directions shown in this paper. The density needs to be updated using the formula The smoothing kernel is If there are no ...
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### Manufactured solution for pressure based 3d incompressible Navier-Stokes solver with wall boundaries

I already successfully verified my solver (SIMPLE-type FVM-method) with the following manufactured solution (3d Taylor-Green vortex) on the solution domain $[-1,1]^3$ with Dirichlet boundary ...
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### What kind of test cases are convenient to use for testing the code for Euler equations of gas dynamics in polar coordinates?

Consider Euler equation of gas dynamics in polar coordinates as  \left( \begin{array}{ccc} \rho \\ \rho u_{r} \\ \rho u_{\theta} \\ E \end{array} \right)_{t} + \frac{1}{r} \left( \begin{array}{ccc}...
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### CFD: Mesh problem [closed]

I wish to study the 2D heat transfer of the soda can using Fluent. For my geometry I took a circle. My problem while meshing the circle; Because i need to mesh it from inside. I used the mapped faced ...
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### Two Dimensional Nozzle Flow

I've been looking at the book "Computational Fluid Dynamics - The Basics With Applications", by John D. Anderson, and his solution for the one-dimensional subsonic-supersonic nozzle flow using the ...
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### Trignometric/Fourier spectral collocation with zero Dirichlet BC in 2D

I am concerned with numerical solution to the following problem on $[0,1]\times[0,1]$. $\dfrac{\partial\theta}{\partial t}+u(x,t).\nabla \theta(x,t)=\kappa \nabla^2\theta(t,x)$ with Dirichlet ...
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### Fluent time step size (transient implicit solver)

I am studying fluid-structure interaction across integrated circuits packaging by using Ansys Fluent (I'm a beginner). Currently I had an issue about the time step size. When I set time step size of ...