Sig WindE/Validation Cases RUSHIL

This is a documentation of my trial to simulate the RUSHIL experiment (main page is: Sig_WindE_-_Validation_Cases) -

I have tried simulating the experiment by Khurshudyan et al.[1], which is a wind tunnel experiment with a 2D hill of several aspect ratios, named also RUSHIL experiment. The latest comparison to it was published by Kasmi and Mason 2010 [2]. Because the top boundary condition is not regular, I had considerable differences with the experiment and have given up for the meanwhile (since it is not similar to real ABL - which is more in my interest - and so not in my focus). Below is what I did for creating a STL surface for the case, just for reference.

Creating the STL surface

The shape of the 2D hill is an analytical function described in [3] as:

$x = \frac{1}{2} \xi \left[ 1+\frac{a^2}{\xi^2+m^2(a^2- \xi^2)} \right]$ for $|x| \leq a$

$z = \frac{1}{2} m \sqrt{a^2-\xi^2} \cdot \left[ 1- \frac{a^2}{\xi^2+m^2(a^2- \xi^2)} \right]$

where $m = \frac{h}{a}+\sqrt{\frac{h}{a}+1}$ and h is the height of the hill ($h = 0.117 [m]$) and a is the length of the hill. $\xi$ is a parameter that changes from 0 to a. The aspect ratio of the hill is 3, 5 and 8.

The experimental setting was:

logarithmic inlet profile with $z_0=0.157 \cdot 10^-3 [m]$, $u_{*} = 0.178 \left[ \frac{m}{s}\right]$ which gives for instance $U_\infty = 3.9 \left[ \frac{m}{s} \right]$ at $z = 1 [m]$

1 The Profile was created with the desired discretization in a spreadsheet program. Column x (1st column) was the width of the hill (arbitrary width), 2nd column is x and the third z. Finally the 3 columns where exported as a csv file RUSHIL_8.csv (This should be according to the .xyz format).

Next, paraview is used to transform the csv into a STL surface, as explained in this thread, an reiterated here:

2 The profile is uploaded in paraview.

3 Open the csv in paraview using the csv reader, choose 1 column for each coordinate.

4 Use the "TableToPoints' filter to obtain an array of points. The columns choice here is important so that the result will be a right hand side coordinate system. For the file above the order is y - x - z

5 Use the delaunay tool to "map" a suface from the point (The Delaunay 2D filter)

6 Save the data, you 'll be able to save it as an stl