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It forms a cone because it depends on a shock wave, and the region enclosed by the shock wave appears conical in shape. See, for example, the apparent cones here: They are also visible here: Wikipedia appears to be fairly clear on why vapor cones are related to shock waves. From the introduction to the article about vapor cones: Atmospheric water ...


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what kind of wings would a person need to fly? long and thin. Human powered flapping-wing aircraft (ornithopter) It seems this couldn't take off under human power alone but, once airborne, could produce enough thrust to overcome drag for up to 145 meters in 20 seconds of flight. to achieve flight on the limited power of the human engine, the ...


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What would be the benefits of rear spoilers in cars, like this one? On cars like that one, there are no significant objective benefits. There are some disadvantages increased weight, so higher fuel consumption increased drag, so higher fuel consumption On racing cars on racing tracks at high speeds, there can be increased downforce on the rear wheels ...


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From Wikipedia: A spoiler is an automotive aerodynamic device whose intended design function is to 'spoil' unfavorable air movement across a body of a vehicle in motion, usually described as turbulence or drag. A rear spoiler is designed to change the flow of air over the rear of the vehicle. This change in air flow increases downforce on the rear of ...


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The spoiler spoil the air flow at the rear side. When the car is cruising, from the frame of reference of the car, air flows around it from front to back. If the air flow is smooth and if there is a large velocity at the rear side then there will be pressure drop. Thus, there is a low pressure at the rear side and higher pressure on the front side, creating ...


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There are many resources on the web which help to answer this question, but not necessarily very recent ones. Take NACA TN 2674 which shows tufted delta wings, or NACA Research Memorandum L57A30. Generally, a delta wing shows separating flow at the leading edge beginning at moderate angles of attack. This separation leads to the formation of a vortex which ...


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It is friction with the outer layers of the atmosphere and the relatively large velocities of the spacecraft which produce these amounts of heat. Hope this is helpful


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The answer is due to the area-Mach number relation for hydrodynamic shocks. G.B. Whitham has a great book (check out Chapter 8) on all sorts of various waves and has a good discussion of this topic. The idea is that one can define the Mach number as a function of the cross-sectional area of a ray tube. The simple form is: $$ \frac{ 1 }{ A } \frac{ d A }{ ...


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The rotation is part of the key to the storm itself. Primarily the pressure and temperature differences are what causes these systems to take the shape and forms that they do. Once a tropical depression starts to form you can already see rotation in the moisture around the low pressure zone, even through it typically looks nothing like a hurricane. Not ...


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Like any object moving through a fluid, a high-speed train distorts the air as it moves through it. Broadly speaking, there are three main regions of flow structure around a high-speed train: the upstream distortion, boundary layer and wake. These can be collectively referred to as the slipstream. The effects of the slipstream on a static observer (e.g. a ...


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The front of the train compresses air which can blow you away, while at the back of the train air rushes back in after the train has displaced it. This backdraft is especially troublesome in closed areas such as subways, where a train exits a small tunnel near a platform and the displaced air rushes back into the vacated tunnel. Next time you see a big truck ...



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