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Line breaks and evanescent waves (2).

Dear colleagues,


Today I have changed my "Einstellungen" (settings?):

I now write E-mails in HTML format. I do not know what

that means -- but trial E-mails sent today to my family

have been free of unwanted line breaks.


More on evanescent waves: They are found in

calculations on a two-dimensional model of the

cochlear channel with x-independent properties

and with negligible viscosity and friction.


If the basilar-membrane (BM) stiffness S is greater

than M * omega^2 [M = BM surface mass density;

omega = 2pi * frequency], then a travelling wave

(TW) results. If, however, S is less than M * omega^2,

then a standing wave occurs. It is called evanescent,

because the _expression_ for the sound pressure

contains a factor of exp(-kappa * x), where kappa can

be determined from the following equation:


kappa * H * tan(kappa * H)

= 2 rho * H *omega^2 / [M * omega^2 -S].


Here, rho = liquid density, and H = half-channel height.


Is that evanescent wave discussed in a published paper?



Reinhart Frosch,
Dr. phil. nat.,
r. PSI and ETH Zurich,
Sommerhaldenstr. 5B,
CH-5200 Brugg.
Phone: 0041 56 441 77 72.
Mobile: 0041 79 754 30 32.
E-mail: reinifrosch@xxxxxxxxxx .