Dynamics Fluids

Question

In an old house, a loose window rattles whenever there's a wind blowing outside the house. If the air inside the house is still and at a pressure 100900 Pa, what is the pressure outside the house if gusts of wind blowing across the surface have a speed of 10.3 m/s. Assume the density of air is 1.28 kg/m³. 

I have no idea how to go about this problem. Any help will be great!

Answer 1

Let

P = 100900 Pa be the pressure inside the house,

p (to be calculated) be the pressure outside the house,

v = 10.3 m/s be the air speed,

ρ = 1.28 kg/m³ be the air density.

This is most likely an application of Bernoulli's principle,

which in this case can be reduced to the equation

p + ρv²/2 = P

Notice that this is another formulation of conservation of energy.

Pressure is potential energy per unit volume and ρv²/2 is kinetic energy per unit volume.

The equation just says that in the absence of any flow to or from the outside, the total energy

outside the house equals total energy inside the house.