Theoretical Solutions for Unsteady Flows Past Oscillating Flexible Airfoils Using Velocity Singularities

2003 ◽  
Vol 40 (1) ◽  
pp. 153-163 ◽  
Author(s):  
D. Mateescu ◽  
M. Abdo
Keyword(s):  
Unsteady Flows ◽  
Flexible Airfoils

Improvements to a dual-time-stepping method for computating unsteady flows

AIAA Journal ◽  
1997 ◽  
Vol 35 ◽  
pp. 1548-1550 ◽  
Author(s):  
S. DeRango ◽  
D. W. Zingg
Keyword(s):  
Unsteady Flows ◽  
Time Stepping ◽  
Dual Time Stepping

Numerical Optimization Algorithm for Unsteady Flows of Rotor based on Web Service

2019 ◽  
pp. -1--1
Author(s):  
Jilin Zhang ◽  
Xuechao Liu ◽  
Jian Wan ◽  
Yongjian Ren ◽  
Binglin Xu ◽  
...  
Keyword(s):  
Web Service ◽  
Optimization Algorithm ◽  
Numerical Optimization ◽  
Unsteady Flows

Aerodynamic Asymmetry Analysis of Unsteady Flows in Turbomachinery

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Kivanc Ekici ◽  
Robert E. Kielb ◽  
Kenneth C. Hall
Keyword(s):  
Harmonic Balance ◽  
Coupling Effect ◽  
Unsteady Flows ◽  
Unsteady Aerodynamic ◽  
Blade Row ◽  
Balance Technique ◽  
Turbomachinery Blades ◽  
Aerodynamic Asymmetry ◽  
Frequency Domain Approach ◽  
Harmonic Balance Technique

A nonlinear harmonic balance technique for the analysis of aerodynamic asymmetry of unsteady flows in turbomachinery is presented. The present method uses a mixed time-domain/frequency-domain approach that allows one to compute the unsteady aerodynamic response of turbomachinery blades to self-excited vibrations. Traditionally, researchers have investigated the unsteady response of a blade row with the assumption that all the blades in the row are identical. With this assumption the entire wheel can be modeled using complex periodic boundary conditions and a computational grid spanning a single blade passage. In this study, the steady/unsteady aerodynamic asymmetry is modeled using multiple passages. Specifically, the method has been applied to aerodynamically asymmetric flutter problems for a rotor with a symmetry group of 2. The effect of geometric asymmetries on the unsteady aerodynamic response of a blade row is illustrated. For the cases investigated in this paper, the change in the diagonal terms (blade on itself) dominated the change in stability. Very little mode coupling effect caused by the off-diagonal terms was found.

On nonlocal fractal laminar steady and unsteady flows

2021 ◽  
Vol 232 (4) ◽  
pp. 1413-1424
Author(s):  
Rami Ahmad El-Nabulsi
Keyword(s):  
Unsteady Flows ◽  
Steady And Unsteady Flows

scholarly journals The Effects of Periodicity Assumptions in Porous Media Modelling

2021 ◽  
Author(s):  
T. O. M. Forslund ◽  
I. A. S. Larsson ◽  
J. G. I. Hellström ◽  
T. S. Lundström
Keyword(s):  
Fluid Flow ◽  
Lattice Boltzmann ◽  
Single Unit ◽  
Unsteady Flows ◽  
Unit Cell ◽  
Porous Bed ◽  
Bed Porosity ◽  
Macroscopic Properties ◽  
Boltzmann Method ◽  
Method Model

AbstractThe effects of periodicity assumptions on the macroscopic properties of packed porous beds are evaluated using a cascaded Lattice-Boltzmann method model. The porous bed is modelled as cubic and staggered packings of mono-radii circular obstructions where the bed porosity is varied by altering the circle radii. The results for the macroscopic properties are validated using previously published results. For unsteady flows, it is found that one unit cell is not enough to represent all structures of the fluid flow which substantially impacts the permeability and dispersive properties of the porous bed. In the steady region, a single unit cell is shown to accurately represent the fluid flow across all cases studied

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