Ed;

 

I would think that unless you were very careful a “Y” would have significant effect because you have a sudden change in the cross-sectional area which would dissipate the pulse energy and/or cause a reflected pulse.  No?

 

Al

 

 

 

   

 

Hi Al,

 

 I agree, it appears that anytime you change the continunity of an airflow it can have adverse effects.  Based on what I have read, Finite-Amplitude Waves (FAW) do indeed get reflected from a change in cross-section.  The extent of that reflection appears to be largely a function of the degree of change in cross-sectional area.  In otherwords, if the change in cross-sectional area is small, the amount of energy reflected is small, if change is large, reflected energy is large.

 

I am not certain what happens if a FAW encounters a "Y", in which the cross sectional area of the two branches of the "Y" equal to the cross sectional area of a single runner feeding them.  The area of the cross-section has not changed which could mean minimal enegry reflected, but the form of it has changed from a single tube to two tubes.  One would think that is bound to have some effect.  The question is "how much?"

 

I am hoping that keeping the cross sectional area for the "Y" and the single runner feeding it the same will minimize any adverse effects.  I intend to do some more research to see if I can get a handle on effects of a "Y" on the FAW.

 

Then, of course, there is the "Y"s effect on the normal airflow.  Again, I believe that if the two ports are opening and closing at the same time having air pushed down a single tube and then splitting into two tubes may not be that bad.  But, not having access to a dyno or the instrumentation that would provide definitive answers, I guess I'll have to try it to find out.

 

Best Regards

 

 

Ed Anderson

 

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