Here's a useful little tool to estimate your wall spacing requirements to achieve a specific y+. It is based on flat plate boundary layer friction estimations. Therefore, it should only be used to put you in the ballpark for mesh sizing. If you found this useful, and have the need for more, visit http://www.stfsol.com. One … Continue reading y+ Calculator
Author: curiosityFluidsAdmin1
Rayleigh–Bénard Convection Using buoyantBoussinesqPimpleFoam
Here is an extremely simple simulation to set up that has a surprisingly beautiful output. In this post, we will simulation the classic Rayleigh–Bénard convection (see Wikipedia) in 3D using the buoyant solver, buoyantBoussinesqPimpleFoam. buoyantBoussinesqPimpleFoam is a solver for buoyant, turbulent, incompressible flows. The incompressible part of the solver comes from the fact that it uses the … Continue reading Rayleigh–Bénard Convection Using buoyantBoussinesqPimpleFoam
Time-Varying Cylinder Motion in Cross-flow: timeVaryingFixedUniformValue
This post is a simple demonstration of the timeVaryingFixedUniformValue boundary condition. This boundary condition allows a Dirichlet-type boundary condition to be varied in time. To demonstrate, we will modify the oscillating cylinder case. Set-Up Instead of using the oscillating boundary condition for point displacement. We will have the cylinder do two things: Move in a … Continue reading Time-Varying Cylinder Motion in Cross-flow: timeVaryingFixedUniformValue
Equations for Steady 1D Isentropic Flow
The equations used to describe steady 1D isentropic flow are derived from conservation of mass, momentum, and energy, as well as an equation of state (typically the ideal gas law). These equations are typically described as ratios between the local static properties (p, T, $latex \rho$) and their stagnation property as a function of Mach … Continue reading Equations for Steady 1D Isentropic Flow
Establishing Grid Convergence
Establishing grid convergence is a necessity in any numerical study. It is essential to verify that the equations are being solved correctly and that the solution is insensitive to the grid resolution. Some great background and details can be found from NASA: https://www.grc.nasa.gov/WWW/wind/valid/tutorial/spatconv.html First, here is a summary the equations and steps discussed here (in case … Continue reading Establishing Grid Convergence
The Ahmed Body
The Ahmed body is a geometric shape first proposed by Ahmed and Ramm in 1984. The shape provides a model to study geometric effects on the wakes of ground vehicles (like cars). Image highlights: In this post, I will use simpleFoam to simulate the Ahmed body at a Reynolds number of 10^6 using the k-omega … Continue reading The Ahmed Body