Off-line exploration of rectangular cellular environments with a rectangular obstacle

2021 ◽  
pp. 1-15
Author(s):  
Fatemeh Keshavarz-Kohjerdi
Keyword(s):  
Rectangular Obstacle

scholarly journals Trapped modes in a waveguide with a long obstacle

2000 ◽  
Vol 403 ◽  
pp. 251-261 ◽  
Author(s):  
N. S. A. KHALLAF ◽  
L. PARNOVSKI ◽  
D. VASSILIEV
Keyword(s):  
Two Dimensional ◽  
Trapped Modes ◽  
Acoustic Waveguide ◽  
Trapped Mode ◽  
Rectangular Obstacle

Consider an infinite two-dimensional acoustic waveguide containing a long rectangular obstacle placed symmetrically with respect to the centreline. We search for trapped modes, i.e. modes of oscillation at particular frequencies which decay down the waveguide. We provide analytic estimates for trapped mode frequencies and prove that the number of trapped modes is asymptotically proportional to the length of the obstacle.

Experimental Study on Regular Wave-Induced Scour and Settlement of a Submerged Obstacle Upon a Fluidized Sandbed

2010 ◽  
Author(s):  
Shiaw-Yih Tzang ◽  
Yung-Lung Chen ◽  
Shan-Hwei Ou
Keyword(s):  
Fluidized Beds ◽  
Suspended Sediment Concentration ◽  
Suspended Sediments ◽  
Sediment Concentration ◽  
Regular Waves ◽  
Rf Test ◽  
Total Settlement ◽  
Test Soil ◽  
Rectangular Obstacle ◽  
Wave Induced

Bed scouring and structure settlement due to interactions of regular waves and a submerged rectangular obstacle in the shallow water regions upon a fluidized fine sandy bed are experimentally investigated. Both impervious and pervious structures are installed on the test soil bed and synchronous measurements of water surface, bed surface, suspended sediment concentration and pore pressures are carried out at locations upstream and downstream. The measurements illustrate that interactions between waves and structures have relatively mild affects on the bed scouring in an unfluidized response. The interactions become more intense in the fluidized responses with significant wave decay over and increasing suspended sediments near above the fluidized beds oscillating with similar period to the loading waves. Meanwhile, the submerged structure starts to settle into the fluidized bed and significant scouring occurs. The interactions are typically greater in a RF test than in a NRF test. More than 90% of the total settlement occurs in a single event of the RF response so that the impervious and pervious structures become half buried and totally buried after the event. The settlements further affect the interactions of following loading waves and the fluidized beds. As a result, scouring on both sides of the half buried impervious obstacle is greater than those of the totally buried pervious structure.

Potential flow over a submerged rectangular obstacle: Consequences for initiation of boulder motion

2019 ◽  
Vol 31 (4) ◽  
pp. 646-681 ◽  
Author(s):  
J. G. HERTERICH ◽  
F. DIAS
Keyword(s):  
Fluid Flow ◽  
Complex Variable ◽  
Potential Flow ◽  
Two Dimensional ◽  
Wake Region ◽  
Local Flow ◽  
Slowing Down ◽  
Complex Variable Methods ◽  
Drag And Lift ◽  
Rectangular Obstacle

AbstractSteady two-dimensional fluid flow over an obstacle is solved using complex variable methods. We consider the cases of rectangular obstacles, such as large boulders, submerged in a potential flow. These may arise in geophysics, marine and civil engineering. Our models are applicable to initiation of motion that may result in subsequent transport. The local flow depends on the obstacle shape, slowing down in confining corners and speeding up in expanding corners. The flow generates hydrodynamic forces, drag and lift, and their associated moments, which differ around each face. Our model replaces the need for ill-defined drag and lift coefficients with geometry-dependent functions. We predict smaller flow velocities to initiate motion. We show how a joint-bound boulder can be transported against gravity, and analyse the influence of a wake region behind an isolated boulder.

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