1. Description and presentation of physical phenomena

1.1 A practical turbulent focus and its laminar counterpart

One of the simplest practical turbulent fireplaces is that used to heat a turbojet or conventional ramjet engine. In these furnaces, fuel is burned in a continuous flow of air at high velocity (around 50 m/s); the fuel (gaseous or liquid) is often injected sufficiently far upstream of the combustion zone, and the air is sufficiently hot, to be able to consider that combustion takes place in an environment where fuel and oxidizer are gaseous and mixed almost perfectly. This is known as a premixed flame.

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