Numerical modelling of sedimentary structures in rivers on Earth and Titan

Abstract

The dif fer ences in the evo lu tion of rivers on Earth and on Ti tan are in ves ti gated. Dy nam i cal anal y sis of the rivers was performed us ing a nu mer i cal pack age CCHE2D de vel oped by the Na tional Cen ter for Com pu ta tional Hydroscience and En gineer ing, Uni ver sity of Mis sis sippi. The model is based on the Navier-Stokes equa tions for depth-in te grated two-di men sional tur bu lent flow and the three-di men sional con vec tion-dif fu sion equa tion of sed i ment trans port. The model en ables in ves ti gation of the evo lu tion of rivers as a func tion of to tal dis charge and other pa ram e ters of the river. Se ries of short (from one to sev eral hours) and long (up to 67 days) sim u la tions were per formed. We have found that three dif fer ent liq uid hy dro car bons con sid ered for Ti tan's rivers give sim i lar ve loc ity fields. It was also found that the sus pended load is the main means of transport in Ti tan's rivers, while in ter res trial ones, for the same dis charge, the bedload could be of the same or der as sus pended load. More over, we sup pose that for spe cific bound ary con di tions, the evo lu tion of rivers on the Earth pro motes the de vel opment of braided rivers, while for the same con di tions evo lu tion on Ti tan fa vours reg u lar me an der ing rivers.

The formation of single-channel and multiple-channel rivers on large slopes

“…On the other hand, the lab o ra tory mod els are much smaller than real rivers. We used the same nu mer i cal pack age as in our pre vi ous work (Misiura and Czechowski, 2015;Witek and Czechowski, 2015), i.e. CCHE2D pack age.…”

Modeling of small river deltas: the dependence of morphology on grain size and discharge

“…Small fans and del tas are much more com mon, yet less ex plored. Space probes have dis cov ered an cient river del tas on Mars and current flu vial ac tiv ity on Ti tan, a moon of Sat urn (see Kereszturi, 2010;Misiura and Czechowski, 2015;Witek and Czechowski, 2015). Most of the Mar tian palaeodeltas are closed-ba sin del tas formed in crater lakes.…”