For each statement, choose whether the statement is true or false, and discuss your answer briefly:

(a) The physical validity of a CFD solution always improves as the grid is refined.

(b) The x-component of the Navier–Stokes equation is an example of a transport equation.

(c) For the same number of nodes in a two-dimensional mesh, a structured grid typically has fewer cells than an unstructured triangular grid.

(d) A time-averaged turbulent flow CFD solution is only as good as the turbulence model used in the calculations.