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no1schuifan
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Hey, sorry if this is posted in the wrong place. Can anyone give me some guidance on how to calculate the theoretical downforce of an upwards curved spolier. Any help will be much appreciated :)
Bernoulli prinicple explains a relationship between static pressure and speed in a work-free environment. I don't understand how Bernoulli principle is used to calculate lift, drag, and turbulence caused by a solid moving through the air and in this case with ground effects. For example, there are stagnation zones fore and aft of an object that move at the same speed of the object, yet their pressures are different. How is this handled with Bernoulli prinicple? A program like xfoil is useful for wings, but this model car with a diffuser is more complicated. I don't see a simple solution.xxChrisxx said:Bernoulli's is perfectly valid for this type of thing as it doesn't require hyper accurate answers, its a simple way of determining the pressure acting under the car with a nice simple eq.
Bernoulli principle is based on the assumption that conversion between pressure and kinetic energy takes place without any work being done, so that the total mechanical energy of the affected air remains constant.xxChrisxx said:What do you mean by work free environment?
In the real world, whenever a solid moves thorugh a fluid or gas, work is done. After the solid passes through a volume of air and after the affected air's pressure returns to ambient, it will have non-zero velocity, reflecting the work done by the solid.How is the flow being worked?
I still don't understand how you're proposing to calculate pressure differential and/or speeds based on a zero AOA flat body or flat pate experiencing ground effects with a diffuser.He wanted a simple and easy way to find a ball park figure for downforce for comparison. Now admittedly this does require some assumptions that strech reality. Basically treating the car as a rectangle or flat plate with zero angle of attack and using the pressure differential either side and treating the car as static. This won't give you a distribution but the OP only mentioned he wanted a figure.
This only occurs in the ideal (imanginary) case where an exchange between pressure and speed2 occurs without performing any net work on the fluid or gas. In a real world situation, the pressure and or speed isn't going to change unless there's some mechanical interaction causing the change (such as a solid moving through the air), so the total pressure is changed, and how this is distributed between static and dynamic pressure depends on the mechanical interaction.no1schuifan said:Firstly, in the bernoull equation: Static pressure + dynamic pressure = constant.
The static pressure is the pressure of the air as sensed by an observer moving at the same speed as that air. The total pressure is the pressure sensed after slowing down the air to the same speed as the observer. The dynamic pressure is the total pressure - static pressure.What exactly is the static pressure?
xxChrisxx said:Air&Space, he's looking at the effect the diffuser will have, not just the wing profile.
The downforce of a wing is calculated by multiplying the wing's surface area by the air density and the square of the wing's velocity. This calculation is then multiplied by the wing's angle of attack and its coefficient of lift.
The downforce of a wing is affected by several factors, including the wing's surface area, angle of attack, air density, velocity, and coefficient of lift. Changes in any of these factors can impact the amount of downforce produced by the wing.
The angle of attack is the angle at which the wing meets the oncoming air. As the angle of attack increases, the downforce of the wing also increases. However, if the angle of attack becomes too steep, the wing can stall and lose its ability to produce downforce.
The coefficient of lift is a measure of the lift generated by a wing at a specific angle of attack. It is directly related to the downforce of the wing, as a higher coefficient of lift means a greater amount of downforce is produced.
Yes, the downforce of a wing can be calculated for any type of aircraft as long as the necessary information, such as surface area and air density, is known. However, the calculations may vary slightly depending on the specific design and characteristics of the wing.