Dynamic pressure on a surface?

In summary, when calculating the pressure exerted on a surface by a moving fluid, both the static pressure and dynamic pressure should be considered. The total pressure can be calculated using the formula P_hyd + P_stat + 1/2 * Rho * V^2, where V is the bulk velocity.
  • #1
Space259
4
0
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
 
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  • #2
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.
 
Last edited:
  • #3
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?
 
  • #4
total pressure = P_hyd + P_stat + 1/2 * Rho * V^2
(V is bulk velocity)
 

1. What is dynamic pressure on a surface?

Dynamic pressure on a surface is a measure of the force exerted by a moving fluid, such as air or water, on an object or surface. It is caused by the fluid's velocity and density.

2. How is dynamic pressure calculated?

Dynamic pressure is calculated by multiplying the density of the fluid by the square of its velocity and dividing by 2. This can be represented by the equation: q = 1/2 * ρ * V2, where q is the dynamic pressure, ρ is the density, and V is the velocity of the fluid.

3. What factors affect the dynamic pressure on a surface?

The dynamic pressure on a surface is affected by the speed and density of the fluid, as well as the shape and orientation of the surface. Other factors such as viscosity and surface roughness can also play a role in the calculation of dynamic pressure.

4. How does dynamic pressure differ from static pressure?

Dynamic pressure is a result of the motion of a fluid, while static pressure is the force exerted by the fluid when it is at rest. Dynamic pressure is typically higher than static pressure, as it takes into account the velocity of the fluid.

5. Why is dynamic pressure important in engineering and aerodynamics?

Dynamic pressure is important in engineering and aerodynamics because it helps determine the loads and stresses on structures and surfaces exposed to moving fluids. It is also used in the design and analysis of aircraft, cars, and other vehicles that interact with air or water. Understanding dynamic pressure is crucial for ensuring the safety and efficiency of these systems.

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