RIPPLE PROFILES MODELED MATHEMATICALLY

FUNDAMENTAL TO THE MECHANICS OF RIPPLE AND DUNE BEHAVIOR IS THE EDDY ZONE IN THE LEE OF THE BED-FORM. A PROFILE MODEL BASED ON IRROTATIONAL FLOW AND INCORPORATING AN EDDY ZONE IS PRESENTED AS AN ADVANCEMENT ON SINUSOIDAL PROFILE MODELS. VELOCITY AND PRESSURE DATA TAKEN FROM A STYROFOAM REPLICA OF THE PROFILE MODEL ARE COMPARED TO THOSE OBTAINED THEORETICALLY ASSUMING IRROTATIONAL FLOW, AND ALSO TO THOSE OBTAINED THEORETICALLY ASSUMING INVISCID ROTATIONAL FLOW. THE LATTER SHOWS GOOD AGREEMENT WITH THE EXPERIMENTAL RESULTS. A COMPLETE MODEL OF BED-FORM BEHAVIOR INVOLVES THE RELATIONSHIP BETWEEN THE BED- FORM PROFILE, THE FLOW OVER THE BED-FORM, AND THE SEDIMENT TRANSPORT OVER THE BED-FORM. THE RELATIONSHIP BETWEEN BED-FORM PROFILE AND THE SEDIMENT TRANSPORT IS EXACT AND WELL KNOWN. A MODEL OF THE RELATIONSHIP BETWEEN THE PROFILE AND THE FLOW IS PRESENTED IN THIS PAPER. /ASCE/