Karthik R
Viscous dissipation is generally talked about in high speed turbulent flows, especially in cases where heat transfer is extremely important. At these speeds, the kinetic energy due to the motion of the fluid (in this case, the turbulent kinetic energy) causes a change in the internal energy of the fluid (thermal energy). This process is irreversible and leads to localized heating of the fluid. The viscous dissipation term shows up in the energy equation of the fluid. Usually, the viscous dissipation term is negligible compared to the diffusive and convective terms. However, in case of aerodynamic heating in high speed transonic and supersonic flows, this term is extremely important.