ON THE SEICHES OF LOCH EARN. 



5L5 



while the effect will not vary from this by more than 4 per cent., if the period of the 

 pressure disturbance lies between 14 - 5 m and 20 "6 m . 



Of course, in practice the maximum result is not usually attained, even if only one 

 oscillation is considered, owing to divergence from the most effective phase of 

 disturbance : also, if there are several periods of the disturbance, and is not unity, 

 the effect produced during the first oscillation may not be equalled in those that follow, 

 or may be partially destroyed. 



m 





S(6, 



hi- 



?// 















1 





















1 







































O 





&--8J8 



T, 

 ~ - 119. 



/ 

 J 









J 





f 





















Fig. 24. 



L6. Example 3. — Consider the effect upon the uninodal seiche during one of its 

 periods of a train of progressive harmonic waves of pressure disturbance given by 



f(w, *) = £asinj -(vt-aw)-<t> I .... (54), 



so that 2-Tr/m is the period, and v the velocity of propagation. Then we have 



r r 



dh\ = fa dww dtn x sin n x t sin {mt - Xw - <f>\ , 



J-l Jn 



where X = ma/v = l-rrajvll, T being the period of the disturbance. 



