Reynolds stress model (RSM)
The Reynold's Stress Model (RSM) is a higher level, elaborate turbulence model. This modelling approach originates from the work by Launders et al (1975). It is usually called a Second Order Closure. In RSM, the eddy viscosity approach has been discarded and the Reynolds stresses are direclty computed. The exact Reynolds stress transport equation accounts for the directional effects of the Reynolds stress fields.