[free.man]

hello everyone.
i am doing some simulation of fluid flow in the 90 degree bending pipe. i want to know relation of velocity inlet variation, compressibility, and pressure drop for mixtures gas flow.

this is my setup:
1. fluid is natural gas (11 species of mixtures gas), modeled as incompressible-ideal-gas. i am considering to use ideal-gas model later. or any suggestion?.
2. velocity will be varied from 0.5 m/s until 180 m/s (velocity, mach number, and Reynolds number attached below).
3. pressure of the system is 0.3 atm(gauge).and environment pressure 1 atm.
4. i use k-w SST turbulent model (my reason is because flow will be always in entrance region, so k-e is not applicable) CMIIW.

my questions are:
1. the fluid is modeled as incompressible-ideal-gas. i am considering to use ideal-gas model later. or any suggestion sir?.
2. based on march number, it will be incompressible and compressible flow can i use pressure based ??. or switch to density based when mach > 0.3 ?
3. where to input the pressure of the system ?. i tried to input inlet pressure gauge 0.3 atm but the result is similar with inlet pressure gauge 0 atm.
4. in some compressible flow simulation tutorial, i saw that they using inviscid model (because of very high Reynolds number). for my model, which one will be better, stay using turbulent model or switch to inviscid ?.

5. i open any suggestion .

thank you for advice.

regards,
free.man

[free.man]

any suggestion??