The calculator computes the pressure, density and temperature ratios in an isentropic flow to zero velocity (0 subscript) and sonic conditions (* superscript).   Select an input variable by using the choice button and then type in the value of the selected variable. The default input variable is the Mach number, and by varying Mach number you can see the effect on Mach angle. You can also select Mach angle as an input, and see its effect on the other flow variables.