Objectives for August

Had a good meeting with my adviser on Friday and we developed a plan for August. The following are the objectives:

• Re-run the model with the new flow conditions - there was a problem with the previous conditions - was off by 1/3 due to configuration of the flume.
• Figure out how to display results using Matlab- Vector and contour plots.
• Run model with many more vertical layers.
• Display results for 2 dunes and calculate the bed shear stress
• Being looking into sediment transport model - start with the continuity equation:

(1-p) dZ/dt = dq/dl

Visualization in ParaView 3.10

ParaView is a free visualization package that I have played with for visualizing OpenFoam model runs. It is fairly flexible and can read many other model outputs. In my case I have a simple CSV files or X,Y,U,V data.

1. Open the CSV file
2. Set up the properties in the Object Inspector tab and click Apply, this will read in the dataset.
3. Select Filters/Alphabetical/Table to Points
4. In the Object Inspector define the X,Y and Z Coordinates. Click Apply.
5. You need to define U and V as vectors.Click the calculator and enter the formula: iHat*U+jHat*V+0*kHat. Click Apply.
6. Now click on the Glif button to create anew Glif.
7. Enter in the symbology for the Glif. I like to use 2D arrows and show the axis.

Vector Plots - Visualizing the Results

Have been trying out some different packages to assist in analyzing the model results. I hate always using Excel as it really never does what I want. Plus with all the open source packages available, it is a shame not to use them. I am currently looking to generate vector plots of the velocity. I used Blue Kenue to extract an ASCII file containing the 3D velocity vectors at a specific time as a 3D Tetra Vector Mesh (t4v). I tried performing an average but Blue Kenue seems to loose the velocity vectors and records only the magnitude.

Anyways I wrote some code to load the t4v into a database where I attempt to normalize the data set. I then use a simple query to extract the profile along a set of nodes to an ASCII file in a CSV format. This can be easily opened by the numerical packages.

Octave - very simple to use and easily handles my non-uniform vector data:

 mdl = csvread("qryProfile_ke.txt");
 h = quiver(mdl(:,8),mdl(:,4),mdl(:,9),mdl(:,7),0.025);


Scilab: Will not handle my non-uniform data without a fight:

mdl2 = read_csv("qryProfile_ke.txt");
mdl = evstr(mdl2)
x = mdl(:,8);
y = mdl(:,4);
u = mdl(:,9);
v = mdl(:,7);

for i = 1:518,
xi = x(i);
yi = y(i);
ui = u(i);
vi = v(i);

champ1(xi,yi,ui,vi,rect=[13,9.9,15.5,10.2],arfact=0.2);
sleep(1);

end;

Anyways here is one of my plots from Octave from the k-epsilon model.

A review and some future research directions - From Best (2005)

Quote from Best (2005): Five areas are then highlighted and discussed as a possible focus for future research:

1. the influence of dune leeside angle upon flow processes in the dune wake and downstream flow field, 
2. the influence of three-dimensionality in dune shape upon the generation of turbulence and distribution of bed shear stress,
3. flow field modification resulting from bed form superimposition and amalgamation, 
4. the scale and topology of dune-related turbulence and its interactions with sediment transport and the flow surface, and
5.  the influence of suspended sediment on the dune flow field and dune morphology.