CFD Online Discussion Forums - transportProperties SettlingFoam

Hi,

Iam trying to simulate a mixture of gas and solid particles. My Simulation works with the dahl tutorial transportProperties but when i enter new properties which are:

Code:

muc muc [ 1 -1 -1 0 0 0 0 ] 1.7e-07;

rhoc rhoc [ 1 -3 0 0 0 0 0 ] 1.3;

rhod rhod [ 1 -3 0 0 0 0 0 ] 7000;

V0 V0 [ 0 1 -1 0 0 0 0 ] ( 0 0 -0.61);

BinghamPlastic is turned off. But what about a and a1 in simpleCoeffs? I cant finde any information about those properties. What do they discribe?
At the moment my simulation doesnt work because my alpha rises in the first time step to 0.84 with a BC of 0.001 at my inlet with U=0.1m/s.