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What you are describing is a characteristic of fluid dynamics known as eddies. As different portions of the fluid flow faster than others, the friction and surface adhesion between the two layers cause swirling of the fluid and reversal of the current, creating a turbulent flow region. It is this same principle that holds a ping pong ball stationary in a ...


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First, thrust = ma = mv/s Next, what type of engine are you referring to? Throw out the first graph, it's all about propulsive efficiency vs speed (props, fans, etc.), not about engine efficiency. Considering exhaust only, the engine has to work to push out the exhaust. This is why rockets have more thrust in space. Also known as "backpressure". ...


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