What is the force exerted on a flat roofed building by wind pressure?

  • Thread starter ku1005
  • Start date
  • Tags
    Wind
In summary, the question involves a flat roofed building with wind blowing over it, resulting in a pressure difference between the inside and outside due to the still air inside. The goal is to calculate the magnitude and direction of the force exerted on the roof using Bernoulli's equation. The dimensions of the roof are needed to calculate the force.
  • #1
ku1005
66
0

Homework Statement



"Wind (density=1.29kgm^-3) blows over a flat roofed building of height 20m at 12ms^-1.The area of he roof is 100m^2.What is the magnitude and direction of the force exerted on the roof if the pressure difference between inside and outside is due solely to the fact that the inside air is still?Assume laminar flow."


Homework Equations



Im really stumped with this Q, I have scanned the net and it seems to involve the Bernoulli Eqn , however, i don't really understand what's occurring, any help appreciated.





The Attempt at a Solution

 
Physics news on Phys.org
  • #2
If you assume that the thickness of the roof is negligible, what's the pressure of the air just outside the roof, where the air is flowing? And the pressure inside where the air is stationary? So, what's the force due to the pressure difference?
 
  • #3
thats the thing, i undererstand where the pressure difference comes from, but not how to calculate it based on the dimensions of the roof?...
 
  • #4
The dimensions of the roof is needed to calculate the force due to the pressure difference. You need to use Bernoulli's equation to calculate the pressure difference. (Hint: The air inside is stationary, while outside, it's moving.)
 

Related to What is the force exerted on a flat roofed building by wind pressure?

1. What is wind pressure/force on a roof?

Wind pressure/force on a roof refers to the force exerted by wind on the surface of a roof. This force is caused by the difference in air pressure between the inside and outside of a building, and can vary depending on factors such as wind speed, building height, and roof shape.

2. How is wind pressure/force on a roof calculated?

Wind pressure/force on a roof is typically calculated using the formula P = 0.00256 x V2 x K, where P is the wind pressure in pounds per square foot (psf), V is the wind speed in miles per hour (mph), and K is a coefficient that takes into account factors such as building height and shape.

3. What are the effects of wind pressure/force on a roof?

The effects of wind pressure/force on a roof can include structural damage, such as roof uplift or failure, as well as water intrusion and damage to roofing materials. It can also contribute to air leakage and energy loss in a building.

4. How can wind pressure/force on a roof be reduced?

To reduce wind pressure/force on a roof, building design and construction should take into account factors such as wind load calculations, building orientation, and proper installation of roofing materials. Additional measures, such as using wind-resistant roofing materials and implementing wind mitigation techniques, can also help to reduce the impact of wind pressure/force on a roof.

5. What safety precautions should be taken to prevent damage from wind pressure/force on a roof?

To prevent damage from wind pressure/force on a roof, regular maintenance and inspection of the roof should be performed to identify any potential weak points or damage. In areas prone to high winds, it may also be beneficial to install hurricane straps or other wind-resistant features. In the event of severe weather, it is important to evacuate the building and seek shelter in a safe location.

Similar threads

How much force is exerted on the roof?
    • Introductory Physics Homework Help
Replies
2
Views
3K
I'm stuck This is a combination of dynamics and free fall
    • Introductory Physics Homework Help
Replies
2
Views
2K
How do wind and air pressure affect a house's roof?
    • Introductory Physics Homework Help
Replies
6
Views
2K
How Does Bernoulli's Equation Apply to Hurricane Wind Pressures on a Roof?
    • Introductory Physics Homework Help
Replies
4
Views
14K
Estimate stopping force of roof versus tornado
    • Introductory Physics Homework Help
Replies
20
Views
3K
Bernoulli's Equation: Finding the net force of wind blowing over a house
    • Introductory Physics Homework Help
Replies
1
Views
5K
Need help identifying the force on a roof as a tornado wind passes over it.
    • Introductory Physics Homework Help
Replies
1
Views
4K
Wind past a flat roof, without hitting the sidewall
    • Classical Physics
Replies
19
Views
4K
Hurricane wind blowing across a flat roof
    • Introductory Physics Homework Help
Replies
2
Views
12K
Fluid Mechanics; Lift Force on a Roof; Bernoulli's Equation
    • Introductory Physics Homework Help
Replies
2
Views
10K

Hot Threads

Recent Insights

Back
Top