bluedlude

i know when to take good info for what it is and when to sit back and laugh. don't **** off the guys that share things most won't. unfortunately people that know something are never going to spoon feed you so don't expect a straight answer, I can see how that may bother you.

Rocket

Correct. This is EXTREMELY important to recognize.

Rocket

Thank you.

Rocket

A buddy of mine models CFD--it's proprietary. We discuss what does what and can calculate speed through the port. There are some "constants" in port design that you can model a port to figure out if it is the right size etc. Like anything the results are not really answers but more just observations from the model instead of actually porting and flowing. Saves a tremendous amount of physical R&D.

:thumbs up:

DC_Legacy

Bob, reguarding the pic which shows a color segragated image of air velocitys, was this image taken from a cut-away of a cylinderhead or how was the image obtained?

edit: so this is a calculated model?

Rocket

It's a model of a intake port from a Japanese 4 valve motor. In this case not Honda. It does have a performance VJ on it. Cylinder head machinist might have some interesting comments.

DC_Legacy

Just curious but since you mentioned the software being proprietary, do you know if this program is being ran from your average PC or a more powerful machine like some weather forecast modeling?

Rocket

It's run on a quad core PC. The mesh calculations take a lot of computing.

DC_Legacy

Good stuff

Alot of good material on your part here lately.

logg_frogg

For more about complicated stick theory read *last chance to see* by Douglas Adams

logg_frogg

Looks like someone beat me to it... I wonder if they can explain why a D shaped port going around a curve or turn is important..


Now look what you made me do... I'm starting to write like you

Rocket

One way to visualize the effect of a flat floor is to compare how water drains out of a round pipe versus a square pipe. It's an easy experiment to do.

Vengeance

To increase the area at the base of the turn to slow velocity, and decrease the area at the height of the turn to increase velocity to prevent shearing of the fluid flow...to keep it laminar.
If you were a member of Larry's(Endyn) old forum you'd already know this stuff.

Nothing wrong with spoon feeding. How does it taste?

logg_frogg

Don't worry, i've done my book reading

The articles on the old Endyne as well as a few others i've read are def worth the time to read!

Aquafina

iTrader: (3)

I don't get what your obsession is with water...

Lighting a cig and blowing smoke through the port is much easier. Then again I can make a picture in my mind of why the D shape works better in a turn.

Rocket

What causes "shearing" if any at da round short turn?

d15Beta

unequal speed on the upper vs lower portion of the port/turn ?

eddys?

logg_frogg

Fuel is heavier than air... it doesn't like to turn corners at the same speed

It's like tring to drive an 81' Coup DeVille around the same corner as an F1 car at high speed

to keep it togeather you need multiple radiuses in you bend

Rocket

That's not really it. And if it does happen, at 7K+ rpms fuel is gonna get in da cylinder and mix and burn efficiently.

Combustion Contraption

But is the fuel really turning when its being shot at the back of the valve and the foor is somewhat flat?

Rocket

Good question. That's why the CFD diagram is helpful. Shows all kinds of large velocities gradient around da valve and into da chamber.

Aquafina

iTrader: (3)

I like to stick my hand out the window just above or below the mirror (96-00 Civic mirror) while on the interstate doing 80-90mph. Every now and then I move my hand directly behind the mirror. Funny how the air there is stale and hot, even though its not under vacuum as a port is. Difference from the flow above and under the mirror...

Vengeance

My answer wasn't good enough? Is there more you'd like to add to that?
Of course not...there never is.

Furyof4

X2 Thanks MOTU

logg_frogg

I was talking about this:






maybe I misunderstood you, what did you mean?