How do I know what the separation point is on a Pressure Coefficient vs Angle graph ?

knight92

Hi there, I just wanted to know how to find out where the separation point is on a Pressure Coefficient against Angle Graph ? I did some research and found out something called an adverse pressure gradient what does it mean ? I know that it does promote a separation point so would a separation point be where the graph has spikes so the gradient goes from negative to positive ? Please tell me according to the graph because right now I am thinking the separation point is at around 1.4,-1.3 [x,y] on the blue lined graph and can there be multiple separation points ? so confused.

I have attached an image for my experimental Pressure Coefficient vs Angle graph and a theoretical pressure coefficient graph. I thought the theoretical pressure coefficient graph didnt show a separation point because there isnt one but it has negative and positive gradients too. Please help and thank you.

Attached Thumbnails

   

boneh3ad

An adverse pressure gradient means that pressure is increasing as you move downstream (aka the flow is decelerating). In relation to your plots, for the first [itex]\pi[/itex] radians, it is any place where the slope of your curve is positive.

The separation points are marked by the points where your Cp distribution goes flat, so roughly [itex]\phi \approx 1.75,4.25[/itex] in your case. The region where it is flat is the separated region.