CONTENTS 

 FIGURES--Continued 



Page 



13 Comparison of ^ computed from the data of this study with 



Shields curve for steady flow and a modified curve of 



Carstens, Neilson, and Altinbilek (1969) . . 43 



14 Rolling-grain ripples and vortex ripples 46 



15 Initial ripple length, independent of a 48 



16 A three-dimensional phase during growth 49 



17 Response of a bed form to a reduction in a 50 



18 Response of a bed form to an increase in a 51 



19 Growth of ripple height with time, n/a as function of (D/a)n. . 53 



20 Growth of ripple length with time 54 



21 Equilibrium A/D as function of 2a/D 56 



22 Equilibrium A/a as function of cj) 58 



23 Equilibrium n/a as function of <i> and a/D 59 



24 Response of a profile to varying strain 61 



25 Final n/A for strained profiles obtained by varying a 62 



26 Compressed, normal, and extended profiles 64 



27 Occurrence of two- and three-dimensional bed forms with the 



0.18-millimeter sand 67 



28 Occurrence of two- and three-dimensional bed forms with the 



0.21-millimeter sand 68 



29 Pairs of final two- and three-dimensional bed forms at 



large and small N 70 



30 Occurrence of two- and three-dimensional ripples on the 



seabed 71 



31 Analogy between (a) transition from laminar to turbulent flow 



in a rough pipe, and (b) transition from oscillatory-flow 



to steady-flow ripples 76 



32 Limits to the occurrence of ripples on the seabed 79 



6 



