# Questions tagged [fluid-dynamics]

The study of the properties of fluids and gases in motion

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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 ...
390 views

### Limitations with dynamical systems vs. PDEs?

As a computational scientist, are there limitations to studying dynamical systems — systems of odes in which each state variable evolves with time — compared to studying PDEs? For instance, it seems ...
151 views

### what do zero real parts of eigenvalues mean? Any good references?

I am solving a 1D advection problem of the the form $$dQ/dt=[A]Q$$ where {Q} is the vector of unknowns and [A] is the matrix of coefficients of spatial discretisation. I have worked out the ...
837 views

### Where do I begin learning CFD?

I am working on some CFD codes - generating adjoint of a CFD model, for example. My background however is in computer science. I have absolutely no clue what the model represents or what it is doing. ...
392 views

### Looking for analytic solutions to time dependent fluid flow problems

I'm looking for analytic solutions to time dependent fluid flow problems (can be compressible or incompressible, Euler or Navier-Stokes equations). The main thing though is that I'd like there to be '...
365 views

### Finite element stabilization schemes for incompressible flow

I am looking for an easy to implement stabilization scheme that can be used with equal order ($P_1-P_1$ or $Q_1-Q_1$) finite elements for fluid flow. Is there something like this or should I stick to ...
170 views

### Finite difference methods in cylindrical and spherical co-ordinate systems

I am quite familiar with finite difference schemes in cartesian coordinates. The key point here is that every point in the cartesian grid is treated equally as the spacing between consecutive points ...
211 views

### Asymptotic error of forward Euler

I'm trying to understand the asymptotic error behaviour of forward Euler (finite difference method), as timesteps are decreased (refined), so I feel trust in the method of manufactured solutions (MMS)....
908 views

### How to set up a shock tube problem such that the solution includes a shock with a specified Mach number

One of the famous and convenient test cases for shock wave modeling is the 1D Sod's shock tube. This is a Riemann problem for the compressible Euler equations of gas dynamics. The initial set up has ...
228 views

### Can one use incompressible flow approximation for fluid flow in heated pipes?

I was wondering if the use of incompressible flow approximation for fluid flow in heated pipes is reasonable. A previous question (Definition of incompressible flow) seemed to focus on Natural ...
1k views

### Looking for a library or algorithms to perfom clipping 3D unstructured meshes by a set of surfaces

We have a 3D (volume) unstructured, possibly hybrid, degenerative irregular mesh data structure that we are capable of generating (mostly composed of hexahedra and general polyhedra, using a mix of ...
162 views

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### Comparison between FEM and FDM methods for flow simulations

What are the main differences between finite element and finite difference approach for incompressible flow simulations? I have a vague idea about how FE methods rely on minimizing the residual over ...
908 views

### 1-D incompressible unsteady Couette Flow Explicit finite differece CFD

I am currently following J.Anderson Jr.'s CFD with basic application and I came into some troubles while coding for my very first CFD problem. As the title suggests I am solving an incompressible ...
664 views

### Discrete conservation and Finite Element methods

What would be the rigorous mathematical expression of the fact that a conservation law discretized with a Finite Element method with Galerkin discretization does not result in a conservative scheme ?
200 views

### Implicit projection method with inflow boundary conditions

I am trying to use a projection method that deals with the viscous effects implicitly to model flow around a cylinder. I'm having trouble figuring out what the boundary conditions should be, ...
362 views

### a few questions on understanding geometric conservation law

I was wondering if anyone could help with understanding the geometric conservation law for moving domains. I came across Link1, and have tried to understood the paper by Farhat et al Link2. So far ...
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### Order of accuracy in a combined scheme

I am trying to use a combination of JST and ROE scheme for the RANS solution of an aerodynamic problem. I notice that the ROE scheme performs poorly in terms of the convergence in the drag counts for ...
161 views

### Reasons to choose LES in stead of RANS models? (turbulence)

In oceanography, is there any particular reason why choosing large eddy simulations in stead of RANS (regardless of the type of flow)? In both cases, 2d simulations would be used (shallow water model)....
190 views

### Resources for solving fluid-structure interaction problems

I would like to get started solving Fluid-Structure interaction problems. I already have some experience with Finite Elements, including my own MATLAB and Julia software packages for developing ...
204 views

### Is it possible to solve Euler equation numerically without using any flux limiter (in DG scheme)?

I have recently learned about Discontinuous Galerkin method to solve differential equations and I was trying to implement it to solve Euler equation. For now, consider the standard Sod Shock Tube Case....
228 views

### Software/code to extract a solenoidal (a.k.a. divergence-free) field from a 2D vector field numerically

Can somebody point me to software/code to extract a solenoidal (a.k.a. divergence-free) field from a 2D vector field numerically? There are a plethora of papers and documents describing how to do ...