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Particle Collision Model for Arbitrary Smooth Shapes

Project Leader
Sindelar Christine, Project Leader
Duration:
01.05.2020-30.04.2023
Programme:
Einzelprojekte
Type of Research
Basic Research
Project partners
Stony Brook University Department of Civil Engineering , NY 11794-4424 Stony Brook, United States (USA).
Contact person: Asst. Prof. Ali Khosronejad;
Function of the Project Partner: Partner
Staff
Habersack Helmut, Sub Projectleader
Gold Thomas, Project Staff
Worf Dominik, Project Staff
Reiterer Kevin, Project Staff
BOKU Research Units
Institute of Institute of Hydraulic Engineering and River Research
Funded by
Fonds zur Förderung der wissenschaftlichen Forschung (FWF) , Sensengasse 1, 1090 Wien, Austria
Abstract
Many rivers worldwide suffer from disturbed sediment dynamics due to human and climate impacts. Understanding sediment processes in rivers is a prerequisite for developing efficient sediment management strategies. When dealing with sediment transport processes in rivers most researchers use a standard or modified form of the critical Shields parameter to predict the incipient motion of a grain size of interest. Despite the wide use of this concept, many studies reveal the apparent lack of a precise threshold value. Rather than the temporally and spatially averaged shear stress at the reach scale, instantaneous forces acting on the grain are responsible for its mobilization. Moreover, particle-particle interactions are a main contributor to sediment entrainment and should thus be explored. The interplay of a fluid (e.g. water) with a solid body (e.g. sediment grains) is modeled in the field of fluid-structure-interactions (FSI). If particle-particle collisions need to be considered additional equations have to be solved. The novel 4D-PTV method for high-resolution spatio-temporal measurements of the flow is an excellent way to study FSI problems experimentally. Collision models between spherical objects and spheroidal objects have been developed recently. Despite the fact that the key role of arbitrary shaped objects and polydisperse particles has been acknowledged in recent publications experimental and numerical studies for high Reynolds number flows and polydisperse arbitrary shaped particles do not yet exist to the best of the authors' knowledge.
The overall project aim is to study collisions which occur in riverine systems and to develop an appropriate collision model. This requires to investigate collisions of arbitrary shaped particles at oblique angles, for diverse Stokes numbers and high Reynolds numbers.
Our approach is threefold. We combine (1) cutting-edge experimental high resolution spatio-temporal 4D-PTV measurements to (2) develop a mathematical lubrication model and (3) implement a numerical collision model based on an immersed boundary method FSI code.
Keywords
Mathematical modelling; Computer simulation; River engineering;
fluid structure interaction; collision model; sediment transport; 3D PTV;
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