# Questions tagged [fluid-dynamics]

The study of the properties of fluids and gases in motion

37 questions
Filter by
Sorted by
Tagged with
4k views

339 views

### In practice, what are the most useful ways to visualize 2d fluid flow, to tell what is happening in the simulation? Esp for verification and debugging

My simulation creates a 2d grid of vectors and scalars (EDIT of velocity, depth etc), at 60 frames per second. Is it correct? It looks sort of right... but who knows? How can I tell what's happening - ...
3k views

There are two general approaches to representing solutions in the discontinuous galerkin method: nodal and modal. Modal: Solutions are represented by sums of modal coefficients multiplied by a set of ...
1k views

### (how to) write simulations that run faster?

I have started using python as the programming language for doing all my assignments in CFD. I have a very little experience in programming. I am from mechanical engineering background and am pursuing ...
3k views

### 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 ...
2k views

### Is there a good, easy-to-use, high quality open source CFD solver out there?

My thesis is on developing numerical methods for model reduction in combustion. I run my methods purely on the chemistry part of combustion simulations, and I have plenty of case studies for 0-D ...
9k views

### Estimating the Courant number for the Navier-Stokes Equations under differing Reynolds number regimes

I am familiar with the Courant-Friedrich-Lewy Condition in as far as it applies to the stability of explicit finite difference schemes for standard parabolic and hyperbolic PDEs. However, when ...
4k views

### simple MHD simulation code for (self) education and play with

I would like some super simple computational code for solving magnetohydrodynamics problems. High accuracy nor performance is not my concern. I wan't it just to visually explore qualitative behavior ...
289 views

### Stabilization of convection-dominated flow and turbulence modeling

Are stabilization techniques for convection-dominated flows like SUPG+PSPG, interior penalty methods, etc. able to handle turbulent flows without tubulence model being employed, at least up to some ...
399 views

### What spatial discretizations work for incompressible flow with anisotropic boundary meshes?

High Reynolds number flows produce very thin boundary layers. If wall resolution is used in Large Eddy Simulation, the aspect ratio may be on the order of $10^6$. Many methods become unstable in this ...
1k views

### 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 ...
1k views

### Is lattice Boltzmann suitable for simulation of incompressible Stokes flow?

We have a flow that is dominated by adhesion forces from the substrate and surface tension from the free surface. The material is nearly solid and at rest first, and gets a bit less solid by heating. ...
2k views

### 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 ...
1k views

### 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 ...
2k views

### 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 ...
651 views

### ENO/WENO component-wise vs characteristic-wise

Can someone give some references to understand what's the differences between a component-wise and a characteristic-wise ENO scheme? If I'm right, the characteristic variables come from the ...
951 views

### Effecient CFD programming techniques

I'm trying to make highly efficient CFD programming complex for solving combustion problems. I've finished writing core which realises mathematical model, and now I'm concerned about code performance. ...
202 views

### Preconditioner for the GMRES method in the Uzawa algorithm

I'm trying to solve \left\{ \begin{split} \frac{\partial u}{\partial t}+(u\cdot\nabla)u-\nu\Delta u+\frac1\rho\nabla p&=f\;\;\;\text{in }\Lambda\\ u&=0\;\;\;\text{on }\partial\...
305 views

### Euler Equation Eigensystem with Gravity in the Energy Flux

I am modifying a conservative form of the Euler equations with gravity in the energy flux (see previous question: Energy Conservation in Conservation Laws with Source Terms) for use in a Riemann ...
357 views

### Potential flow around a non-symmetric obstacle using stream functions

I've seen that there is a way to use the finite differences method, on a cartesian orthogonal grid, to perform calculations on potential flow about an obstacle without using the Neumann conditions, ...
169 views

### A simple PDE solution question

I need to ask a question about partial derivatives. I want to solve this equation (steady state, one dimensional continuity equation): $$\frac{\partial (\rho u)}{\partial z}=0$$ which is equivalent to:...
2k views

### Stability of numerical method for 1D Burger's equation

I am trying to solve 1D viscous Burger's equation numerically and I cannot apply von Neumann analysis because the equation is non-linear. How do I predict the stability criteria for my system? I also ...