What is the problem of numerical diffusivity?
(a) The simulated model has a higher diffusivity than the actual flow
(b) The simulated model has a lower diffusivity than the actual flow
(c) The simulated model has a different diffusivity than the actual flow
(d) The simulated model has a zero diffusivity
This question was addressed to me by my college professor while I was bunking the class.
The doubt is from Convection-Diffusion Problems in chapter Convection-Diffusion Problems of Computational Fluid Dynamics