Robert Morein wrote:


I'm afraid this is incorrect. The heuristics usually used
to describe this effect apply equally well to an ideal
system where a massless, infinitely compliant and lossless
piston is driven by a force function.


1. You can't contradict what I said with a heuristic. See
http://www.hyperdictionary.com/dictionary/heuristic

I'm not trying to; I'm trying to cast doubt on the heuristic
description. All too often when this is attempted, the
result is a failure of intuition.


2. The "heuristic", by which you probably mean approximation, is exactly
that and no more, a very useful approximation.

Can you state an expression for it? That, if it is
justifiable from first principles, eliminates heuristics.


3. The subject under discussion is whether the "heuristic" breaks down in a
meaningful fashion. This is the very core of the discussion. If Doppler
effect influences the sound output, then, to the extent which it does, the
"heuristic" is invalid.

No, it is whether it has any validity at all.


4. I do not imply by the above that Doppler is important, or is not. But
please understand that the following is an equivalence relationship:

a. If Doppler is unimportant, then the heuristic you mention is, for all
practical purposes, a very good one.

It is just hand waving to this point.


Bob
--

"Things should be described as simply as possible, but no
simpler."

A. Einstein