A novel nonreflecting boundary condition for unsteady flow

2013 ◽  
Vol 74 (1) ◽  
pp. 59-72 ◽  
Author(s):  
Baha Zafer ◽  
Can F. Delale
Keyword(s):  
Boundary Condition ◽  
Unsteady Flow ◽  
Nonreflecting Boundary Condition

scholarly journals The DtN nonreflecting boundary condition for multiple scattering problems in the half-plane

2012 ◽  
Vol 217-220 ◽  
pp. 1-11 ◽  
Author(s):  
Sebastian Acosta ◽  
Vianey Villamizar ◽  
Bruce Malone
Keyword(s):  
Boundary Condition ◽  
Multiple Scattering ◽  
Half Plane ◽  
Scattering Problems ◽  
Nonreflecting Boundary Condition

scholarly journals Vector fitting realisation of exact time domain modal nonreflecting boundary condition

2010 ◽  
Vol 46 (11) ◽  
pp. 760 ◽  
Author(s):  
K. Bavelis ◽  
C. Mias
Keyword(s):  
Boundary Condition ◽  
Time Domain ◽  
Vector Fitting ◽  
Exact Time ◽  
Nonreflecting Boundary Condition

The LBE Simulation and PIV Experimental Study on a Novel Viscous Pump

2005 ◽  
Author(s):  
Fan Yang ◽  
Shuhong Liu ◽  
Jinwei Li ◽  
Yulin Wu
Keyword(s):  
Boundary Condition ◽  
Unsteady Flow ◽  
Cross Sections ◽  
Lattice Boltzmann ◽  
Moving Boundary ◽  
Flow Problem ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Low Reynolds Numbers ◽  
Moving Boundary Condition

A numerical study and PIV investigation of flow in a novel viscous-based pumping device appropriate for microscale applications is described. The device, essentially consisting of a rotating cylinder eccentrically placed in a channel, is shown to be capable of generating a net flow. The two shape cross-sections of cylinders, the circular and four semi-elliptic lobed contour are studied, which is the steady and unsteady flow problem, respectively. The lattice Boltzmann equation (LBE) simulations at low Reynolds numbers are carried out to study the influence of various geometric parameters, which the results are compared with the PIV experiment ones. The unified solid curved wall boundary condition based on interpolation and the balance of momentum on the wall of the LBE simulation is used in steady and unsteady flow, and the moving boundary condition is also used in the latter. The numerical results indicated that the more effective pumping and better performance is obtained with the decrease of Reynolds number, as well as the increase regular degree of cylinder cross-section.

scholarly journals Nonreflecting boundary condition for the wave equation

2002 ◽  
Vol 138 (2) ◽  
pp. 309-323 ◽  
Author(s):  
Usaf E. Aladl ◽  
A.S. Deakin ◽  
H. Rasmussen
Keyword(s):  
Boundary Condition ◽  
Wave Equation ◽  
Nonreflecting Boundary Condition

Large-Scale DES Analysis of Unsteady Flow Field in a Multi-Stage Axial Flow Compressor at Off-Design Condition Using K Computer

2015 ◽  
Author(s):  
Kazutoyo Yamada ◽  
Masato Furukawa ◽  
Satoshi Nakakido ◽  
Akinori Matsuoka ◽  
Kentaro Nakayama
Keyword(s):  
Boundary Condition ◽  
Unsteady Flow ◽  
Gas Turbines ◽  
Large Scale ◽  
Axial Flow ◽  
Axial Flow Compressor ◽  
Eddy Simulation ◽  
Multi Stage ◽  
Flow Phenomena ◽  
Flow Compressor

The paper presents the results of large-scale numerical simulations which were conducted for better understanding of unsteady flow phenomena in a multi-stage axial flow compressor at off-design condition. The compressor is a test rig compressor which was used for development of the industrial gas turbine, Kawasaki L30A. The compressor consists of 14 stages, the front two stages and the front half stages of which were investigated in the present study. The final goal of this study is to elucidate the flow mechanism of the rotating stall inception in the multi-stage axial compressor for actual gas turbines, and according to the test data it is considered that the 2nd stage and the 5th or 6th stage are suspected of leading to the stall. In order to capture precise flow physics in the compressor, a computational mesh for the simulation was generated to have at least several million cells per passage, which amounted to 650 million cells for the front 2-stage simulation and two billion cells for the front 7-stage simulation (about three hundred million cells for each stage). Since these were still not enough for the large-eddy simulation (LES), the detached-eddy simulation (DES) was employed, which can calculate flow fields except near-wall region by LES. The required computational resources were quite large for such simulations, so the computations were conducted on the K computer (RIKEN AICS in Japan). The simulations were well validated, showing good agreement with the measurement results obtained in the test. In the validation, the effect of the boundary condition for the casing wall was also investigated by comparing the results between the adiabatic boundary condition and the isothermal boundary condition. As for the unsteady effect, the wake/blade interaction was investigated in detail. In addition, unsteady flow phenomena in the present compressor at off-design condition were analyzed by using data mining techniques such as vortex identification and limiting streamline drawing with the LIC (line integral convolution) method. The simulation showed that they could be caused by the corner separation on the hub side.

scholarly journals Exact Nonreflecting Boundary Condition For Elastic Waves

2000 ◽  
Vol 60 (3) ◽  
pp. 803-819 ◽  
Author(s):  
Joseph B. Keller ◽  
Marcus J. Grote
Keyword(s):  
Boundary Condition ◽  
Elastic Waves ◽  
Nonreflecting Boundary Condition

Three-Dimensional Non-Reflecting Boundary Condition for Linearized Flow Solvers

2010 ◽  
Author(s):  
Paul J. Petrie-Repar
Keyword(s):  
Boundary Condition ◽  
Unsteady Flow ◽  
Steady Flow ◽  
Three Dimensional ◽  
Far Field ◽  
Two Dimensional ◽  
Flow Equations ◽  
Flow Simulations ◽  
Unsteady Aerodynamic ◽  
2D And 3D

A three-dimensional (3D) non-reflecting boundary condition for linearized flow solvers is presented. The unsteady aerodynamic modes at the inlet and outlet (far-field) are numerically determined by solving an eigen problem for the semi-discretized flow equations on a two-dimensional mesh. Unlike previous methods the shape of the far-field can be general and the non-uniformity of the steady flow across the far-field is considered. The calculated unsteady modes are used to decompose the unsteady flow at the far-field into modes. The direction of each mode is determined, and incoming modes are prescribed and outgoing modes are extrapolated. The results of 2D and 3D inviscid linearised flow simulations using the new boundary condition are presented.

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