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مکانیک::
نقطه سکون
In the designing of the con- tour in the end wall region, the intent is to reinforce the horseshoe vortex as it develops close to the stagnation point of the profile.
Note that considerable variations in the local heat transfer coefficient, from a peak near the stagnation point beneath the jet to low values away from the jet, make the task of measuring cooling effectiveness in impingement systems a tricky proposition.
On the upstream side of the stagnation point the curve falls more steeply than on the downstream side, where an attenuation in the drop at about 1.4 jet diameters from the hole axis is more pronounced.
A secondary peak in the region is due to action from adjacent jets, experiencing greater deflection downstream than the stagnation point in the presence of cross flow.
A symmetric jet profile covers an increasing area moving away from the jet axis, and hence coefficient values at the axis counteract to increase the Nusselt number at the stagnation point.
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