Harmonics and Intake

[wstrass at eastman.com]

To: BOWLING --INTERNET Bowling
cc: DIY     --INTERNET DIY

From: Wayne Strasser (CED)
_______________________________________________________________________
Subject: Harmonics and Intake

Hello Bruce:

I have a question/concern about your "optimum intake runner
calculation".  I have not seen the estimating equation(s)
used on this page, but I do assume based on your
introductory paragraph that the equations ignore load
(charge density) and are only a function of RPM.  I would
argue that the mean density of the charge in an important
factor when estimating the harmonic properties of the
flowing gas stream.  Here is my reasoning:

Since this is a problem of transient momentum and energy
transfer, we can revert to fundamental Eulerian continuum
mechanics to provide necessary conservation laws (mass,
momentum, energy, and angular momentum)..

Assuming the following:

1.  Isentropic, irreversible system

 a. The momentum flux (double dot product between the shear
    stress tensor and the diadic product grad v) and the heat
    flow (grad dotted into heat flux) are allowed to vanish from
    the equations
 b. The time scale needed to change the temperature of the
    gas stream is much greater than the time scale of velocity
    profile development

2.   Equilibrium local velocities, temperatures, and
     pressures

     a.  No shock wave present
     b.  No mechanical energy dissipated

it can be shown that the speed and amplitude of the pulses
"bouncing" around in the intake medium are a direct function
of both the mean and instantaneous charge density.  I would
like to know more about your calculations and how they were
empirically determined.  Thanks for your time.

_______________________________________________________________________
        Wayne Strasser
        Polymer Development
        wstrass at eastman.com