where Cp is the drag coefficient of the actual grain, as obtained from 

 Table 1, and DSF is from Equation 7. 



A Reynolds number (R D ) was back calculated for the data from the 

 3rd Street pier transect using DSF values and again following Briggs, 

 et al. (1962) : 



R .= ./(DSF) (R ) 2 (21) 



p v n 



This computation was made as a check on the determination of the DSF 

 value since Rp should in effect be equal to the previously computed R e . 



After computation of the R e values it became obvious that the 

 Reynolds numbers of the particles involved were quite low. The product 

 of R e x Cd was computed for many of the samples to obtain a comparison 

 with the established constant value of R e x Cd = 24 (Equation 4) for 

 particles within the realm of Stokes' law. 



Mineralogy. The percentage by number of heavy minerals and rock 

 and shell fragments was determined for each of the sieve fractions from 

 the mixture of Virginia Beach sands (Table 2). 



RESULTS AND DISCUSSION 



Shape Factor 



Table 3 presents the triaxial measurements and Corey Shape Factors 

 for individual grains from fractions retained on Sieves Nos. 18 and 230. 

 This table has been included for the use of those who may wish to try 

 other shape factors based upon these measurements. The respective 

 average S.F. for these fractions was 0.67 (S = 0.15) and 0.63 (S = 0.13). 

 As can be seen from the standard deviations, S, variation around these 

 means is not too great and therefore ,. our estimated average shape 

 factor for each fraction represents the sample adequately. Because 

 there is practically no difference in shape factor between the two 

 fractions, they may be combined to obtain an average shape factor for 

 sands of all sizes in the strip of beach under study. This is justified 

 by the fact that no difference in shape factor is to be expected in 

 grains of sizes intermediate between those measured when the latter, 

 close in size to the largest and smallest grains present in the beach, 

 failed to show any. The combined average S.F. is 0.65. For conven- 

 ience in using the tables in Zeigler and Gill (1959) this shape factor 

 was taken as 0.7. According to the U. S. Inter-Agency Committee on 

 Water Resources (1958) a shape factor of 0.7 is about average for 

 natural sediments. 



