Inclusion of collisional return-to-isotropy in the MP-PIC method

► MP-PIC is a numerical method for the calculation of dense particle/fluid flows. ► We include a new model for particle-collision return-to-isotropy in MP-PIC. ► MP-PIC computational parcels undergo random motions, mimicking motions of real particles. ► Kinetic transport of particle mass, momentum, and energy are now calculated more accurately. ► Results of MP-PIC calculations of impinging gas/particle jets are now more realistic.