# derivePressureMS Subroutine

## public recursive subroutine derivePressureMS(fun, varSys, elempos, time, tree, nElems, nDofs, res)

Calculate species pressure both for gas and liquid model In case of gas mixture, it is partial pressure where as in liquid mixture this is not valid. However, it is used to compute mixture pressure and then the kinematic_pressure from the mixture pressure. Formula to calculate pressure: $p_k = c^2_s ( \rho_k \phi_k )$ here, $\rho_k$ - species density, \ $\phi_k$ - species molecular weight ratio, \

### Arguments

TypeIntentOptionalAttributesName
class(tem_varSys_op_type), intent(in) :: fun

Description of the method to obtain the variables, here some preset values might be stored, like the space time function to use or the required variables.

type(tem_varSys_type), intent(in) :: varSys

The variable system to obtain the variable from.

integer, intent(in) :: elempos(:)

Position of the TreeID of the element to get the variable for in the global treeID list.

type(tem_time_type), intent(in) :: time

Point in time at which to evaluate the variable.

type(treelmesh_type), intent(in) :: tree

global treelm mesh info

integer, intent(in) :: nElems

Number of values to obtain for this variable (vectorized access).

integer, intent(in) :: nDofs

Number of degrees of freedom within an element.

real(kind=rk), intent(out) :: res(:)

Resulting values for the requested variable.

Linearized array dimension: (n requested entries) x (nComponents of this variable) x (nDegrees of freedom) Access: (iElem-1)fun%nComponentsnDofs + (iDof-1)*fun%nComponents + iComp

## Variables

TypeVisibilityAttributesNameInitial
integer, private :: statePos
integer, private :: iElem
integer, private :: iLevel
integer, private :: dens_Pos
integer, private :: iField
integer, private :: depField
integer, private :: elemOff
type(mus_varSys_data_type), private, pointer:: fPtr
real(kind=rk), private :: mass_dens