First commit of branch performance:

Bugs fixed:
- Solved an issue with particles being injected with infinite velocity
  resulting in Inf velocity in some cells of the output files.
- Particles are now equally distributed in cylindrical geometry along
  the radial direction.

New features:
- Particles now have their own weight that is recalculated when the
  particle moves to a new cell. This avoid the reduction of density at
  r = 0.

Cases:
- Added a case of Argon flow around a cylinder to measure performance
  and future improvements.

src/modules/moduleInput.f95

@@ -74,11 +74,11 @@ MODULE moduleInput
       IF (.NOT. found) CALL criticalError('Reference radius not found','readReference')
 
       !Derived parameters
+      v_ref     = DSQRT(kb*T_ref/m_ref)  !reference velocity
       sigma_ref = PI*(r_ref+r_ref)**2    !reference cross section
       L_ref     = 1.D0/(sigma_ref*n_ref) !mean free path
       ti_ref    = L_ref/v_ref            !reference time
       Vol_ref   = L_ref**3               !reference volume
-      v_ref     = DSQRT(kb*T_ref/m_ref)  !reference velocity
 
     END SUBROUTINE readReference
 
@@ -104,7 +104,10 @@ MODULE moduleInput
       IF (.NOT. found) CALL criticalError('Required parameter time not found','readCase')
 
       !Convert simulation time to number of iterations
-      tmax = INT(time/(ti_ref*tau))
+      tmax = INT(time/tau)
+
+      !Makes tau non-dimensional
+      tau = tau / ti_ref
 
     END SUBROUTINE readCase