How to Calculate Pressure Exerted by an Engine in a Vacuum?

[Space259]

Hello all,

How would I calculate the pressure exerted on a surface by an engine in a vacuum, for example, if a lander was landing on Mars, I'm trying to calculate the pressure exerted on the surface by the exhaust. Should I simply be looking at P=F/A or should I be looking at dynamic pressure?

Thanks in advance

 

[russ_watters]

For pressure exerted on a surface by a moving fluid perpendicular to it, the static pressure is equal to the velocity pressure, and p=f/a applies.

 

[Space259]

Hi Russ,

Thanks for your reply, so where does the dynamic pressure come into it? If you were to calculate the Dynamic Pressure what would you be calculating?

 

[jaap de vries]

total pressure = P_hyd + P_stat + 1/2 * Rho * V^2
(V is bulk velocity)