Numerical simulation of viscous oscillatory flow past four cylinders in square arrangement

2011 ◽  
Vol 27 (2) ◽  
pp. 212-232 ◽  
Author(s):  
P. Anagnostopoulos ◽  
Ch. Dikarou
Keyword(s):  
Numerical Simulation ◽  
Oscillatory Flow ◽  
Flow Past ◽  
Four Cylinders

Modeling of mass transfer in biofilms in oscillatory flow conditions using k-ɛ turbulence model

2003 ◽  
Vol 3 (1-2) ◽  
pp. 201-207
Author(s):  
H. Nagaoka ◽  
T. Nakano ◽  
D. Akimoto
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Turbulence Model ◽  
Uptake Rate ◽  
Oscillatory Flow ◽  
Substrate Uptake ◽  
Flow Conditions ◽  
Mass Transfer Mechanism ◽  
Substrate Uptake Rate ◽  
Good Agreement

The objective of this research is to investigate mass transfer mechanism in biofilms under oscillatory flow conditions. Numerical simulation of turbulence near a biofilm was conducted using the low Reynold’s number k-ɛ turbulence model. Substrate transfer in biofilms under oscillatory flow conditions was assumed to be carried out by turbulent diffusion caused by fluid movement and substrate concentration profile in biofilm was calculated. An experiment was carried out to measure velocity profile near a biofilm under oscillatory flow conditions and the influence of the turbulence on substrate uptake rate by the biofilm was also measured. Measured turbulence was in good agreement with the calculated one and the influence of the turbulence on the substrate uptake rate was well explained by the simulation.

Numerical simulation of transonic flow past an F-16A aircraft configuration using CASPER

2000 ◽  
Author(s):  
Yoshiatsu Oki ◽  
Takeshi Sakata ◽  
Naoki Uchiyama ◽  
Takeshi Kaiden ◽  
Takeshi Andoh
Keyword(s):  
Numerical Simulation ◽  
Transonic Flow ◽  
Flow Past

Oscillatory flow past a circular cylinder in a rotating frame

1997 ◽  
Vol 345 ◽  
pp. 101-131
Author(s):  
M. D. KUNKA ◽  
M. R. FOSTER
Keyword(s):  
Circular Cylinder ◽  
Steady Flow ◽  
Stagnation Point ◽  
Oscillatory Flow ◽  
Numerical Solutions ◽  
Initial Conditions ◽  
Temporal Integration ◽  
Oncoming Flow ◽  
Flow Past ◽  
Rear Stagnation Point

Because of the importance of oscillatory components in the oncoming flow at certain oceanic topographic features, we investigate the oscillatory flow past a circular cylinder in an homogeneous rotating fluid. When the oncoming flow is non-reversing, and for relatively low-frequency oscillations, the modifications to the equivalent steady flow arise principally in the ‘quarter layer’ on the surface of the cylinder. An incipient-separation criterion is found as a limitation on the magnitude of the Rossby number, as in the steady-flow case. We present exact solutions for a number of asymptotic cases, at both large frequency and small nonlinearity. We also report numerical solutions of the nonlinear quarter-layer equation for a range of parameters, obtained by a temporal integration. Near the rear stagnation point of the cylinder, we find a generalized velocity ‘plateau’ similar to that of the steady-flow problem, in which all harmonics of the free-stream oscillation may be present. Further, we determine that, for certain initial conditions, the boundary-layer flow develops a finite-time singularity in the neighbourhood of the rear stagnation point.

Numerical Simulation Study on the Asymmetric Structures of Oscillatory Flow Field in a Baffled Tube Reactor

2004 ◽  
Author(s):  
Yong-Wen Wu ◽  
Jia Wu
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flows ◽  
Oscillatory Flow ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Structured Grid ◽  
Tube Reactor ◽  
Oscillating Boundary ◽  
The Asymmetry ◽  
Laminar And Turbulent Flows

The oscillatory flow in a baffled tube reactor provides a significant enhancement of radial transfer of momentum, heat and mass and a good control of axial back mixing at a wide range of net flow rate. But little has been known about reliable details of the three-dimensional structure of flow field in this kind of flow because most published studies in the area were based on the two-dimensional simulation techniques. This paper implemented a three-dimensional numerical simulation study on the asymmetry of flow pattern in the baffled tube reactor which was observed experimentally. A systematic study by numerical simulation was carried out which covered a range of oscillatory Reynolds number (Reo) from 100 to 5,000 and employed models respectively for laminar and turbulent flows. It was found in the simulation that under symmetric boundary conditions the transition from axially symmetric flow to asymmetric one depended on the numerical technique employed in simulation. With a structured grid frame the transition occurred at Reo much greater than that with an unstructured grid frame, for both laminar and turbulent flows. It is not rational that the onset of the transition changes with the accuracy of numerical technique. Based on the simulation results, it was postulated that the asymmetry appeared in simulations with symmetric boundary conditions might result from the accumulation of calculation errors but the asymmetry observed in experiments might result from the slight asymmetry of geometry which exists inevitably in any experiment apparatus. To explore the influence of the slight asymmetry of geometry, the effect of the eccentricity of baffles and the declination of oscillating boundary were studied by use of the finite volume method with a structured grid and adaptive time steps. The simulation result showed that both the eccentricity of baffles and the declination of oscillating boundary have obvious influence on the asymmetry of flow patterns for laminar and turbulent flow. More details were discussed in the paper.

scholarly journals Direct numerical simulation of bubble behavior in oscillatory flow

1991 ◽  
Vol 89 (4B) ◽  
pp. 2015-2015
Author(s):  
D. Z. Zhang ◽  
A. Prosperetti ◽  
A. S. Sangani
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Oscillatory Flow ◽  
Bubble Behavior
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