NO. 124 - March 1961 



" Experimental Study on the Solitary Wave Reflection Along 

 a Straight Sloped Wall at Oblique Angle of Incidence" by 

 T. C. Chen. 



The reflection pattern of a solitary wave impinging on a 

 sloping wall and some accompanying phenomena were studied 

 in a laboratory ripple tank. The angle of incidence of the 

 wave was varied between zero and 90° and the slope angle 

 of the wall with the horizontal, between 20° and 150°. 

 It was found that curved ripples developed when incident 

 waves hit a wall of slope less than 65° approximately. 

 As the angle of incidence increased, an envelope of these 

 ripples formed and became large enough beyond a certain 

 angle of incidence, depending on slope, to look like a 

 reflected wave but remained curved as were the ripples. 

 For a relatively steep wall slope, larger than 65°, re- 

 flection was regular, but the angle of incidence at which 

 a straight reflected wave occurred depended on the slope 

 of the wall. For a wall with negative slope Mach re- 

 flection took place for wave incident angles between 30° 

 and 35o. Mach reflection ceased and regular reflection 

 occurred when the angle of incidence was 45°. Three types 

 of wave behavior relative to breaking were observed and 

 found to be related to the angle of incidence. 



NO. 125 - March 1961 



' On the Description of Short-Crested Waves " by 

 J. E. Chappelear. 



A mathematical description of short-crested waves is 

 presented, based on the procedure of Fuchs which has been 

 systematized using the procedure of Stokes (a formal 

 power-series expansion about the case of zero height). 

 The solution presented has a limitation to the relative 

 size of the crest length and wave length, but this is 

 believed to be mathematical rather than physical, de- 

 pending on the assumed form of solution. A comparison 

 is afforded between properties of short-crested and 

 long-crested waves. 



