Question

For the vector form of the finite element model of momentum and continuity equations MΔ+K^11Δ+K^12P=0 what is the order of matrix F if the order of M is 2n x 2n?

(a) 2n x 1

(b) 1 x 2n

(c) m x 2n

(d) 2n x m

I got this question during an online interview.

This question is from Velocity topic in division Flows of Viscous Incompressible Fluids of Finite Element Method

Answer 1

The correct answer is (a) 2n x 1

For explanation: In the vector form, the terms M and K^11 are of the order 2n x 2n, K^12 is of the order 2n x m, K^21 is of the order m x 2n. The equation MΔ+K^11Δ+K^12P=F^1 gives the vector form, where F is force matrix, M is a mass matrix, K^11 is related to velocity term, K^12 is related to the pressure term, P is the pressure matrix, and Δ is the velocity matrix. Note that