Intersting Information - Technical Artical

[49-1183904562]

Not sure where to post this and if any of you have ever come across it but it looked like good reading.

Rick

[200cfm]

Very good article. Laminar flow offers faster air speed than turbulent flow. That was a learning point. And laminar flow is fastest down the center of the pipe. I thought it be important to have pressure balance throughout the cross section areas of the pipe for best flow. Can anyone explain why laminar flow is faster with CSA pressure imbalances?

[86rocco1]

I'd think that whenever there's greater flow, there would, out of necessity, be a bigger pressure imbalance, more flow implies a greater average pressure, but they're always be a boundary layer next to the surface where the the pressure is near zero, put those two facts together and you get a larger imbalance.

[CraigAPD]

I would have thought the velocity gradient peaking in the centre of the bore was more to do with wall friction?

[200cfm]

What if it were not round but square or even rectangular. Assuming no curves where would the fastest air be? Still down the middle or ???

[gofaster]

Nice article! I really liked the last 3d model showing the CFD analysis of a fully dynamic engine cycle.

Has anybody on the forum used the "4stHEAD" software mentioned in the article? I have been reading Professor Gordon Blair's book "Design and Simulation of Four-Stroke Engines", which is very interesting. Regretably, I'm somewhat under educated, so I trip over some of the math. I wondered if the soft ware would help me through some of it, because I understand it was also designed by Professor Blair and his Associates.

[ThomasVaught]

Quote:

"Laminar flow offers faster air speed than turbulent flow. That was a learning point. And laminar flow is fastest down the center of the pipe. "

I went back through my old NACA papers and found that graph and the testing in some pre 1950 air flow work. They measured the shape with a pressure tap grid.

Tom V.

[jsa]