Bed shear stress is an important measure of benthic habitats since it related to many ecological processes. In this study, we focused on the fluctuating characteristics in rough-bed open-channel flows. The roughness element method was adopted mimic natural rough beds and Improved Delayed Detached Eddy Simulation (IDDES) model used obtain comprehensive information about near bed. Three arrangeme...

One of the key requirements for deriving more realistic ice sheet models is to obtain a good set of basal measurements that enable accurate estimation of bed roughness and conditions. For this purpose, 3D tomography of the ice bed has been successfully implemented with the help of angle of arrival estimation (AoA) algorithms such as multiple signal classification (MUSIC) and maximum likelihood ...

The resulting properties of parts fabricated by powder bed fusion additive manufacturing processes are determined by their porosity, local composition, and microstructure. The objective of this work is to examine the influence of the stochastic powder bed on the process window for dense parts by means of numerical simulation. The investigations demonstrate the unique capability of simulating ma...

[1] Field studies suggest that bedrock incision by granular flows may be the primary process cutting valleys in steep, unglaciated landscapes. An expression has been proposed for debris flow incision into bedrock which posits that erosion rate depends on stresses due to granular interactions at the snout of debris flows. Here, we explore this idea by conducting laboratory experiments to test th...

At the smallest scales of sediment transport in rivers, the coherent structures of the turbulent boundary layer constitute the fundamental mechanisms of bedload transport, locally increasing the instantaneous hydrodynamic forces acting on sediment particles, and mobilizing them downstream. Near the critical threshold for initiating sediment motion, the interactions of the particles with these u...

investigation on local scour phenomenon downstream of impinging jets is very complicated. different parameters such as geometry of stream, characteristics of flow and sediments have great influences on the scour phenomenon. the present study is preceded to numerical modeling of scouring by impinging jet via ssiim 2 model founded on a physical model tests. the numerical model is calibrated for r...

In this study, a three-dimensional (3D) numerical model based on the smoothed particle hydrodynamics (SPH) approach was developed to simulate near-shore current flows over rough topographic surface in coastal area, where are shallow and demonstrate strong turbulent characteristics. The program is open-source code SPHysics ( http://www.sphysics.org ), two major improvements made treat turbulence...

Safe, precise landing in difficult planetary terrain, including areas that are rocky, heavily sloped, or both, requires remote sensing of the surface in order to choose an appropriate landing site. While active or passive optical sensors might seem appropriate for this application, we are developing an alternate approach based on a millimeter-wave electrically scanned phased array radar. A rada...

In this paper the rapidly varied unsteady flow caused by the failure of a dam in a rectangular dry bed horizontal channel has been studied both theoretically and experimentally. Experiments with dam-break flows in smooth and rough channel have been carried out. Comparisons have been made between measured depth hydrographs at different stations along the channel and analytical solution of Ritter...