All Questions
Tagged with computational-physics fluid-dynamics
154
questions
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Add pressure gradient to Falkner-Skan (FS) boundary layer (BL) equations and solve numerically for arbitrary $P(x)$
I have read quite a few tutorials / watched several clips on the derivation of the Falkner-Skan boundary layer equations using similarity and then solution using RK solvers such as ...
- 21
2
votes
1
answer
63
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Finite differencing for velocity cross terms?
In writing down the Navier-Stokes equation I have encountered two equations as follows:
$$ 4\frac{\partial^2 v_x}{\partial x^2} + \frac{\partial^2 v_x}{\partial y^2} + 3\frac{\partial^2 v_y}{\partial ...
- 21
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31
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Admissible solutions for waves propagating in a fluid medium obtained from Fast Fourier Transform
Given a two-dimensional pressure distribution $p(x,y)$ in a fluid medium, we can perform Fast Fourier transform to obtain the amplitude and phase spectra. The 2D-FFT (and eventually, the IFFT) ...
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28
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How to model the vacuum-solid interface?
Consider an ordinary object, e.g. metal or an insulator placed in a simulation mesh to simulate a CFD physics problem, creating a solid-vacuum interface. I cannot model this as a dense ideal gas as it ...
- 196
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46
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Intertial finite-size effects in fluid simulations
A gradient $\nabla \rho$ in the density field $\rho$ of fluids at thermodynamic equilibrium is suppressed at a rate given by $D \nabla^{2} \rho$, allowing to measure the diffusivity $D$ of the fluid ...
- 895
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42
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Inverting a bubble interface to recover the level set function
I have access to some high quality CFD data that includes 2D and 3D level set functions for simulations of bubbles. Masking the level set function using a heaviside is easy and it is a fast way to get ...
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2
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40
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Hydrodynamic interactions and finite-size corrections
In molecular dynamics simulations of fluids it is known that diffusion coefficient $D$ of fluid simulated under periodic boundary conditions in a cubic box with size $L$ decays with a factor $\frac{1}{...
- 895
2
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65
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Diffusive finite-size effects of fluids in periodic boundary conditions
Consider a fluid of given density $\rho [\frac{kg}{cm^{3}}]$ in thermal equilibrium at a given temperature $T [K]$. If at time $t_{0}$ we apply a force $f(\vec{r}, t) = f_{0}\delta(t-t_{0})\delta(\vec{...
- 895
5
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1
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111
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Acoustic finite-size effects of simulated fluids under periodic boundary conditions
Consider a fluid simulated in a finite box of specific size. An impulse to the fluid element at the center in a given direction is physically expected to propagate at the speed of sound and attenuate ...
- 895
2
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2
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166
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Book on numerical solution of PDEs
I would like to learn how to solve partial differential equations (first and second order, e.g. Poisson, etc...) numerically with finite differences. Which book can be recommended if one want it to ...
1
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1
answer
77
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Does anyone have a good source for writing a Finite Volume Solver
As a pet project I want to try and write my own finite volume solver for a two-phase flow problem. However, while I understand the basics of FEM I have never written a code that solves anything before....
1
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1
answer
128
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Finite Differencing with Incompressible Navier-Stokes Equations (Only Advection)
I'm trying to improve the advection method in a 2D-windfield. The Navier-Stokes Equations (NSE) are currently used for the influence of pressure, viscosity,... I am just focusing on the convective ...
- 13
1
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1
answer
45
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How does corner transport differ from advection schemes?
I was curious what the difference between corner transport and regular advection schemes.
Usually models approximate advection by plugging in $1 D$ flux approximations for $\frac{d Qx}{dx}$, $\frac{d ...
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46
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Modeling fluid flow in extremely small pores (or channels) compared to the component
I want to model a non-wetting fluid flowing into tiny pores of a component using Navier-Stokes.
Just for you to visualize, say I have a 2D rectangular component of dimensions $L*W$, and within that ...
- 23
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10
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Droplet Breakup model solely for charged droplets in electric field?
At the moment I am trying to simulate charged droplets and their berakup in an homogeneous electrical field in vacuum. I am using a VoF-Method, but as the droplets get smaller and smaller I would need ...
- 11