Different thermal boundary conditions affected the flow field, then affected the heat transfer, rotation was the main reason of the affection, viscous heating and buoyancy were two important factors.

Viscous flow patterns are set up in the motor, increasing heat transfer to the propellant surface through greater mass transfer.

In the following soak (shut-in) phase, the well is shut in for days to allow the heat to dissipate in the reservoir and the heavy oil to heat up and become less viscous.