Mean and turbulent flow structure during the amalgamation process in fluvial bed forms

摘要: [1] Fluvial channels present bed forms such as dunes and ripples that alter instantaneous hydrodynamics parameters flow velocities, water surface profiles, shear stresses, Reynolds stresses create turbulent coherent structures are significantly different from those presented in flat conditions. It is known LES-based models more suitable than RANS to reproduce the complex around forms. Herein, a LES model applied describe mean structure under superimposed Three cases were simulated: RUN I (train of ripples), II (superimposed forms), III (amalgamated forms). The modeling was performed using free condition allow develop undulations boils on caused by effect Some important conclusions this study are: division high low stoss side dune, progression field topology III, type found each stage. region related turbulence production, which streamwise velocity fluctuations (where strips streaks) associated modification morphology. Horseshoes Vortices (THV) frequent other two rolls frequent). Finally, frequency bursting events increased decreased III. Implications detailed into processes also discussed.