Hi all,
The result of my model doesn't sound rational when I do particle tracing for fluid flow. I have a 3D hydrological model which has two different layer. The hydraulic conducity for the first layer is 1E-4 and second (bottom) layer 1E-9. for the flow modeling, I used Darcy's law phisycs which work fine I think! I wanted to release a particles from a falt surface which located in the second layer and see the residence time and trajectory length for each particles. Therefore, I assumed Massless particles and defined a grid surface for the release. Two auxiliary dependent variables were introduced for the particle residence time and trajectory length as it has been explain in particle tracing for fluid flow user guid! I assume the unit for trajectory line is meter cause in auxiliary dependent variable for integration along trajectory the equation is d(rp)/ds=R in which the unit of R is 1/m (I know that I can change the unit of dependent variable to m as well, but its 1 at the moment).
The problem is that the distance between the release pont and the end point is around 9 meter (the model is 10 X 10 X 10 cubic meter); but the result of trajectory length is in rder of 1E4 (i.e., 10000 meter)!!!!
So, there should be a silly mistack in my model which I can't find it! Attcahed is my COMSOL model which I have cleared the mesh and solution to decrease the size . Any suggestion would be really appreciated!
Bests, /Brian