Stability of a Free Surface Flow with a Bed Layer and Its Relation to Sand Wave Generation: Theoretical Solution and Verification Test

This chapter delves into the following discussions. A flow system in an alluvial channel is considered. The study background is given and the study objectives are stated followed by a presentation of the ASCE classification of bed forms. A review of existing theoretical work is given and the most important findings are noted. The study basis is presented by stating the main study hypothesis (MSH), the time domain hypothesis (TDS), as well as the sand wave characteristics and the study premises. The theoretical flow model, a two-layer free surface flow with a thin bed layer, is presented. The long wave stability solution for subcritical flow of the system is established by applying the GKH model. The stability solution is illustrated and discussed in detail. The effect on the interface stability by the free surface as well as by the bed layer are described. Validity ranges of the results are discussed. Laboratory tests for the purpose of verifying the results are described, and conclusions are established based on the tests.