Evanescent waves in bathtubs (2). ("reinifrosch@xxxxxxxx" )


Subject: Evanescent waves in bathtubs (2).
From:    "reinifrosch@xxxxxxxx"  <reinifrosch@xxxxxxxx>
Date:    Fri, 15 Apr 2011 14:49:36 +0000
List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>

------=_Part_4391_26152566.1302878976612 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Dear colleagues, The liquid-particle motion in the 1.15-hertz oscillation described yesterda= y differs appreciably from one point in the bath water to the other. In the= studied case, the waterline at the two long walls oscillates up and down, = staying horizontal. If the amplitude of that oscillation is assumed to amou= nt to 2 cm, then for the assumed dimensions (surface width 55 cm, water hei= ght 30 cm) the water particles at the center of the surface oscillate horiz= ontally (in a direction perpendicular to the long walls) with an amplitude = of about 2.13 cm. The water particles at the center of the bottom oscillate= in the same direction with an amplitude of only about 0.75 cm, and those a= t the bottom of the long walls of the assumed cubic bathtub do not oscillat= e at all. So the designation of that standing surface wave as an evanescent= wave is justifiable. Is this simple bathtub wave described in textbooks? I= f yes, then the step to the evanescent waves relevant to acoustics and (pos= sibly) to cochlear mechanics would be small of course.=20 Reinhart. Reinhart Frosch, Dr. phil. nat., CH-5200 Brugg. reinifrosch@xxxxxxxx . ------=_Part_4391_26152566.1302878976612 Content-Type: text/html;charset="UTF-8" Content-Transfer-Encoding: quoted-printable <html><head><style type=3D'text/css'> <!-- div.bwmail { background-color:#ffffff; font-family: Trebuchet MS,Arial,Helv= etica, sans-serif; font-size: small; margin:0; padding:0;} div.bwmail p { margin:0; padding:0; } div.bwmail table { font-family: Trebuchet MS,Arial,Helvetica, sans-serif; f= ont-size: small; } div.bwmail li { margin:0; padding:0; } --> </style> </head><body><div class=3D'bwmail'><FONT size=3D2>Dear colleagues,<BR>The l= iquid-particle motion in the 1.15-hertz oscillation described yesterday dif= fers appreciably from one point in the bath water to the other. In the stud= ied case, the waterline at the two long walls oscillates up and down, stayi= ng horizontal. If the amplitude of that oscillation is assumed to amount to= 2 cm, then for the assumed dimensions (surface width 55 cm, water height 3= 0 cm) the water particles at the center of the surface oscillate horizontal= ly (in a direction perpendicular to the long walls) with an amplitude of ab= out 2.13 cm. The water particles at the center of the bottom oscillate in t= he same direction with an amplitude of only about 0.75 cm, and those at the= bottom of the long walls of the assumed cubic bathtub do not oscillate at = all. So the designation of that standing surface wave as an evanescent wave= is justifiable. Is this simple bathtub wave described in textbooks? If yes= , then the step to the evanescent waves relevant to acoustics and (possibly= ) to cochlear mechanics would be small of course. <BR>Reinhart.<BR><FONT si= ze=3D2><BR></FONT>Reinhart Frosch,<BR>Dr. phil. nat.,<BR>CH-5200 Brugg.<BR>= reinifrosch@xxxxxxxx .</FONT> </div></body></html> ------=_Part_4391_26152566.1302878976612--


This message came from the mail archive
/var/www/postings/2011/
maintained by:
DAn Ellis <dpwe@ee.columbia.edu>
Electrical Engineering Dept., Columbia University