Turbulent Flow 





Connecting 



1 











Tidal 



Hole Diameter 



A 



ength 



Lag 



Measured 







Nomo 



Actual 



a I 



cxe- 



Ho 



Ho' 



Ho' 



' N ! 



Period 



in. 



ino 





(ft,) 



(sec) 



- TT 



ft„ 



fto 



Hn 



N 



Hn 



70oS 



1/8 



.261 



227 







2o3 



-0O65 



0O25 



0025 



loOOO 



0O8I6 



3o27 i 





1 



I0OO4 



16„08 







Oo9 



-0O25 



„026 



,026 



loOOO 



16o3 



627 



138o0 



1/16 



c0625 



a^o 







33o8 



-.490 



0O242 



0OO35 



0U6 



00093 



„0384 



U0o5 



1/8 



o267 



227 







6o5 



-0O92 



0O23 



0O23 



1»000 



o322 



UoO 





1/A 



.350 



132 







loO 



-oOU 



0O27 



0O27 



IcOOO 



o9/i8 



35ol 



Experimental Accuracy 



The elevations on the tide graphs can be measured to +_ OoOOl foot,, The 

 time intervals can be read to at least +_ 2 seconds and perhaps even more 

 accurately o The maximum range of Hq was about O0O25 feet and Hq' went as low 

 as O0OO3 so that the error in elevation measurements was roughly +_ U% and +_ 35^ 

 with the smaller error occurring with the larger ranges. As the lag increased, 

 the percentage error in the measured values decreased but was always greater 

 than i_ 5%o The remarks on accuracy are made as an explanation of the scattering 

 of the experimental points , shown on Figures 1 and 2, 



Sample Calculation 



(a) A tide gags is to be located in a 4--inch well and connected to the 

 main tidal basin by 4-0 feet of \ inch standard wrought iron pipe. 



Hq = O0O25 fto 



L = 40 fto 



R = Oc0152 fto 



w = 62o4 IbSo/cuo ft< 



A = 123 



a 



."5 



// s 2o35 X 10 -" Ibo sec, 

 T = 138 oO seco 

 or ^ 0o044,7 rado/seco 



C - 8 //PC L^ - 8 X 2,35 X O447 X 10"^ x 40 x 123 = 2,87 



62„4 X (,0152)^ 



■^O ,nP 



wR a 



- tana© = C; cc 



70^ 



40^ 



© = - 70o7 X 140 o 5 =^ 27o5 sec (neasured 31 + 2 seco) 

 360 



Hq' = Hq cos ccg = O0O25 X 0„331 = O0OO8 ft, 



Difeasured H„« = 0,003 + 0,001 ft. 



34 



