Consider the discretized form of an equation given by ( frac{ partial( rho u phi)}{ partial x}=-a( phi_c- phi_u)+b( phi_d- phi_c). ) For this numerical scheme to be TVD, what is the condition?(Note: u, c and d are the flow variables at the far upwind, upwind and downwind schemes).

Consider the discretized form of an equation given by ( frac{ partial

1.	Consider the discretized form of an equation given by ( frac{ partial( rho u phi)}{ partial x}=-a( phi_c- phi_u)+b( phi_d- phi_c). ) For this numerical scheme to be TVD, what is the condition? (Note: _u, _c and _d are the flow variables at the far upwind, upwind and downwind schemes).
A.	a 0;b 0;0 a+b 1
B.	a 0;b 0;0 a+b 1
C.	a 0;b 0;0 a-b 1
D.	a 0; 0;0 a-b 1
Answer» B. a 0;b 0;0 a+b 1