Degree

Doctor of Philosophy (PhD)

Department

Civil and Environmental Engineering

Document Type

Dissertation

Abstract

The Lower Mississippi River Physical Model (LMRPM), housed at the LSU Center for River Studies on the Baton Rouge, LA Water Campus, is a distorted, movable bed model comprising the lower 195 miles of the Mississippi River from Donaldsonville through the Head of Passes into the Gulf of Mexico. Since the LMRPM was designed to replicate the hydraulics (i.e., flow and river stages) and bulk non-cohesive sediment transport, the model lightweight sediment must replicate both the incipient motion and two-dimensional dune characteristics (height and length). In addition, the model scale and distortion require that the sediment time scale be determined empirically.

A series of flume experiments were conducted to evaluate the model sediment response to prototype scaled conditions in terms of the incipient motion, dune formation and sediment time scale. Results showed that the stresses in terms of Shields parameter well satisfied the Shields criterion which suggests that overall the local turbulence generated at the initiation of model particles motion is consistent with the theoretical approaches for bed evolution in rivers with sand. Scales dunes in the experiments reflected dune lengths and heights similar to those found in the prototype reach. Finally, flume and model results demonstrate that a model sediment time scale of 6600 provides good replication of prototype (bulk) bed morphodynamics.

Date

3-18-2019

Committee Chair

Willson, Clinton

Share

COinS