- #1

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## Main Question or Discussion Point

Could someone explain the image we see below of a fully separated and stagnated flow over a wing

if we were to focus on where the flows rejoin on the trailing edge we see above a fully stagnated flow DP=0

The static pressure here in the boundary layer above where the flows rejoin should be equal to the total pressure as there is no flow

SP=TP-0

Below we have a fast moving fluid with high DP as evidenced by tight streamlines

SP=TP-DP

If we were to draw a control surface line (pink line) parallel to the streamlines we have a Static Pressure gradient towards the higher speed lower pressure bottom flow

The image however shows the streamlines crossing the control surface into the higher pressure zone

How is this so

Is this the Kutta condition where SP at the trailing edge (where the flow rejoins) is stagnated therefore equal

If so we are seeing the diffusion (of the bottom flows) higher momentum towards the lower momentum area

If so shouldn't this be only at the stagnation point and further afield the pressure gradient would dominate ? We do see this as the lower streamlines actually become tighter past the trailing edge ?

if we were to focus on where the flows rejoin on the trailing edge we see above a fully stagnated flow DP=0

The static pressure here in the boundary layer above where the flows rejoin should be equal to the total pressure as there is no flow

SP=TP-0

Below we have a fast moving fluid with high DP as evidenced by tight streamlines

SP=TP-DP

If we were to draw a control surface line (pink line) parallel to the streamlines we have a Static Pressure gradient towards the higher speed lower pressure bottom flow

The image however shows the streamlines crossing the control surface into the higher pressure zone

How is this so

Is this the Kutta condition where SP at the trailing edge (where the flow rejoins) is stagnated therefore equal

If so we are seeing the diffusion (of the bottom flows) higher momentum towards the lower momentum area

If so shouldn't this be only at the stagnation point and further afield the pressure gradient would dominate ? We do see this as the lower streamlines actually become tighter past the trailing edge ?