Documentation of tangential coefficient of restitution in StandardWallInteraction is incorrect
Summary
Documentation of tangential coefficient of restitution in StandardWallInteraction.H is incorrect.
The documentation in the header says " mu 0; // optional - restitution coeff"
However, if you set mu = 1 then line 234 (v2212) results in the tangential velocity being reduced to zero which is what you should get for a perfectly inelastic collision, i.e. a coefficient of restitution of 1. " U -= mu_*Ut;"
What is the current bug behaviour?
Setting a value of mu = 1 behaves as a perfectly inelastic collision instead of a perfectly elastic collision.
What is the expected correct behavior?
Setting a value of mu = 1 should not alter the tangential velocity upon impact with the wall. Conversely setting mu = 0 should reduce the particle tangential velocity to that of the patch.
Possible fixes
The documentation should state the mu is equal to 1 minus the coefficient of restitution. This is how it is implemented in the code.
Or the code (line 234) should be changed so that mu behaves as a coefficient of restitution.