Quote:
Originally posted by nicozeg
In WW block, water is thrown in the middle of the channel, where it has two ways to go. This is not the ideal jet because it has some drag from the sides, but after the impact to the bottom it has to choose side.
When the jet is placed at the beginning of the channel, there’s only one way to go. My fear in this case is that water doesn’t wait for the impact at the bottom and just choose the shortest path, avoiding the corner where we want it to go.
All this are theories I’m making, trying to explain why I didn’t see an improvement with the nozzle. Does it make sense?
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The WW "jet" is not an ideal jet, but that "drag" that you refer to as actually a highly turbulent convection layer. Swings and roundabouts sort of thing. What is lost in terms of impingement, is gained in terms of boosted convection from the fins.
I am however a little fuzzy on the exact jet impingement theory and how it pertains to striking surfaces with "furniture" about, but it would seem to me that what you're saying about the single path out makes sense. There would indeed be a tendency for the fluid to take the shortcut, however this does not mean that it won't be doing something useful, depending on the balance of fin height and how far up the fins (whether radial or parallel) the heat travels.