caa a22 4500 528785435 20181217030312.0 cr unu---uuuuu 180924e20131004xx s 000 0 eng 10.3929/ethz-b-000073465 doi 10.1038/srep02858 doi (ETHRESEARCH)oai:www.research-collection.ethz.ch:20.500.11850/73465 Numerical modeling of the wind flow over a transverse dune [Elektronische Daten] [Ascânio D. Araújo, Eric J.R. Parteli, Thorsten Pöschel, José E. Andrade, Hans J. Herrmann] Sci Rep Open access ethresearch Transverse dunes, which form under unidirectional winds and have fixed profile in the direction perpendicular to the wind, occur on all celestial objects of our solar system where dunes have been detected. Here we perform a numerical study of the average turbulent wind flow over a transverse dune by means of computational fluid dynamics simulations. We find that the length of the zone of recirculating flow at the dune lee — the separation bubble — displays a surprisingly strong dependence on the wind shear velocity, u*: it is nearly independent of u* for shear velocities within the range between 0.2 m/s and 0.8 m/s but increases linearly with u* for larger shear velocities. Our calculations show that transport in the direction opposite to dune migration within the separation bubble can be sustained if u* is larger than approximately 0.39 m/s, whereas a larger value of u* (about 0.49 m/s) is required to initiate this reverse transport. Creative Commons Attribution 3.0 Unported http://creativecommons.org/licenses/by/3.0 ethresearch Nonlinear phenomena ethresearch Fluid dynamics ethresearch Araújo Ascânio D. joint author Parteli Eric J.R. joint author Pöschel Thorsten joint author Andrade José E. joint author Herrmann Hans J. joint author Scientific Reports London : Nature Publishing Group 3, p. 2858 2045-2322 http://hdl.handle.net/20.500.11850/73465 text/html WWW-Backlink auf das Repository (Open access) 1 Journal Article ethresearch ETHRESEARCH 856 40 http://hdl.handle.net/20.500.11850/73465 text/html WWW-Backlink auf das Repository (Open access) ETHRESEARCH 700 1- Araújo Ascânio D. joint author ETHRESEARCH 700 1- Parteli Eric J.R. joint author ETHRESEARCH 700 1- Pöschel Thorsten joint author ETHRESEARCH 700 1- Andrade José E. joint author ETHRESEARCH 700 1- Herrmann Hans J. joint author ETHRESEARCH 773 0- Scientific Reports London : Nature Publishing Group 3, p. 2858 2045-2322 BK010053 XK010053 XK010000 ETHRESEARCH ETHRESEARCH ETHRESEARCH Journal Article Open access