Questions about Pressure Update Term 'dp' in smoothers.F90

[xiaoyangqh]

Hello community,

I'm currently using the version mdolab/public:u20-gcc-ompi-stable and I have two questions regarding the code in smoothers.F90, specifically within the subroutine named executeDADIStep:

1. Why is the pressure update term dp formulated as follows:

dp = ((ovr*p(i,j,k) + factK &
      - gm1*(ovr*w(i,j,k,irhoE) - v2))*dw(i,j,k,irho) &
      + gm1*(dw(i,j,k,irhoE) - w(i,j,k,ivx)*dw(i,j,k,imx) &
      - w(i,j,k,ivy)*dw(i,j,k,imy) &
      - w(i,j,k,ivz)*dw(i,j,k,imz)))*temp_value

Instead of directly using the equation of state p=gm1*(w(i,j,k,irhoE) - 0.5*w(i,j,k,irho)*v2) to update the pressure?

2. In the commentary located near this code snippet, it is mentioned:

! Compute the pressure update from the conservative
! updates. The expression used below is valid even if
! cp is not constant. For the calorically perfect case,
! cp is constant, it can be simplified to the usual
! expression, but not for variable cp.

The comment suggests that the expression for dp remains valid even when gamma or cp (specific heat at constant pressure) changes. However, the update term for dp does not seem to include any changes in the specific heat ratio gamma or cp. Is there an issue here?

I appreciate any guidance or clarification on these matters. Thank you for your support.