Airfoil Mesh Generated with curiosityFluidsAirfoilMesher.py Here I will present something I've been experimenting with regarding a simplified workflow for meshing airfoils in OpenFOAM. If you're like me, (who knows if you are) I simulate a lot of airfoils. Partly because of my involvement in various UAV projects, partly through consulting projects, and also for testing … Continue reading Automatic Airfoil C-Grid Generation for OpenFOAM – Rev 1
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
Mach 1.5 flow over 23 degree wedge – rhoCentralFoam
In this post I will simulate inviscid Mach 1.5 flow over a 23 degree wedge of a finite height. A finite height is required because at Mach 1.5 the leading edge shock-wave is detached for a deflection angle of 23 degrees. Without a finite height the shock wave standoff distance would be indeterminate. Here is … Continue reading Mach 1.5 flow over 23 degree wedge – rhoCentralFoam
Tutorial: Creating curves in blockMesh
In this post, I'll give a simple example of how to create curves in blockMesh. For this example, we'll look at the following basic setup: As you can see, we'll be simulating the flow over a bump defined by the curve: $latex y=H*\sin\left(\pi x \right) $ First, let's look at the basic blockMeshDict for this … Continue reading Tutorial: Creating curves in blockMesh
Creating synthetic Schlieren and Shadowgraph images in Paraview
Experimentally visualizing high-speed flow was a serious challenge for decades. Before the advent of modern laser diagnostics and velocimetry, the only real techniques for visualizing high speed flow fields were the optical techniques of Schlieren and Shadowgraph. Today, Schlieren and Shadowgraph remain an extremely popular means to visualize high-speed flows. In particular, Schlieren and Shadowgraph … Continue reading Creating synthetic Schlieren and Shadowgraph images in Paraview
Solving for your own Sutherland Coefficients using Python
Sutherland's equation is a useful model for the temperature dependence of the viscosity of gases. I give a few details about it in this post: https://curiosityfluids.com/2019/02/15/sutherlands-law/ The law given by: $latex \mu=\mu_o\frac{T_o + C}{T+C}\left(\frac{T}{T_o}\right)^{3/2}&s=1$ It is also often simplified (as it is in OpenFOAM) to: $latex \mu=\frac{C_1 T^{3/2}}{T+C}=\frac{A_s T^{3/2}}{T+T_s}&s=1$ In order to use these equations, … Continue reading Solving for your own Sutherland Coefficients using Python
Tips for tackling the OpenFOAM learning curve
The most common complaint I hear, and the most common problem I observe with OpenFOAM is its supposed "steep learning curve". I would argue however, that for those who want to practice CFD effectively, the learning curve is equally as steep as any other software. There is a distinction that should be made between "user … Continue reading Tips for tackling the OpenFOAM learning curve
Normal Shock Calculator
Here is a useful little tool for calculating the properties across a normal shock. If you found this useful, and have the need for more, visit http://www.stfsol.com. One of STF Solutions specialties is providing our clients with custom software developed for their needs. Ranging from custom CFD codes to simpler targeted codes, scripts, macros and … Continue reading Normal Shock Calculator