Question

The bulk viscosity term in the compressible flows are discretized as ___________

(a) summation of bulk viscosity and area at the faces

(b) product of bulk viscosity and volume at the cell centre

(c) product of bulk viscosity and area at the faces

(d) summation of fluxes over the faces

This question was posed to me by my college director while I was bunking the class.

My query is from Compressible Flows topic in division Incompressible Flows & Compressible Flows of Computational Fluid Dynamics

Answer 1

The correct choice is (d) summation of fluxes over the faces

The best explanation: The bulk viscosity term in the momentum equation is a volume integral. This is converted into a surface integral. This surface integral is then discretized as the summation of fluxes over the faces of the control volume.