Here is a simple online calculator to find the value of Isentropic flow relation between pressure and total Pressure. In the below calculator, enter the values for density, total density, specific heat ratio and click calculate to know the relationship between the pressure and total pressure. A process during which the entropy remains constant is called as isentropic process. This calculator is applied in pumps, gas compressors, turbines, nozzles and diffusers.
If the density , total density and specific heat ratio values are 12, 5 and 8.
P / Pt = (ρ / ρt)γ
P / Pt = (12 / 5)^8
= 1100.7531417599998 N/m^2