Unsteady two-dimensional potential-flow model for thin variable geometry airfoils

Wind Energy ◽  
2010 ◽  
Vol 13 (2-3) ◽  
pp. 167-192 ◽  
Author(s):  
Mac Gaunaa
Keyword(s):  
Potential Flow ◽  
Flow Model ◽  
Variable Geometry ◽  
Two Dimensional ◽  
Potential Flow Model

A Two-Dimensional Potential Flow Model of the Wave Field Generated by a Semisubmerged Body in Heaving Motion

1988 ◽  
Vol 32 (02) ◽  
pp. 83-91
Author(s):  
X. M. Wang ◽  
M. L. Spaulding
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Potential Flow ◽  
Flow Model ◽  
Second Order ◽  
Two Dimensional ◽  
Third Order ◽  
The Third ◽  
Potential Flow Model ◽  
Good Agreement

A two-dimensional potential flow model is formulated to predict the wave field and forces generated by a sere!submerged body in forced heaving motion. The potential flow problem is solved on a boundary fitted coordinate system that deforms in response to the motion of the free surface and the heaving body. The full nonlinear kinematic and dynamic boundary conditions are used at the free surface. The governing equations and associated boundary conditions are solved by a second-order finite-difference technique based on the modified Euler method for the time domain and a successive overrelaxation (SOR) procedure for the spatial domain. A series of sensitivity studies of grid size and resolution, time step, free surface and body grid redistribution schemes, convergence criteria, and free surface body boundary condition specification was performed to investigate the computational characteristics of the model. The model was applied to predict the forces generated by the forced oscillation of a U-shaped cylinder. Numerical model predictions are generally in good agreement with the available second-order theories for the first-order pressure and force coefficients, but clearly show that the third-order terms are larger than the second-order terms when nonlinearity becomes important in the dimensionless frequency range 1≤ Fr≤ 2. The model results are in good agreement with the available experimental data and confirm the importance of the third order terms.

A Free-Streamline Model for Bluff Bodies in Confined Flow

1977 ◽  
Vol 99 (3) ◽  
pp. 585-592 ◽  
Author(s):  
V. J. Modi ◽  
S. E. El-Sherbiny
Keyword(s):  
Potential Flow ◽  
Bluff Body ◽  
Flow Model ◽  
Circular Cylinders ◽  
Bluff Bodies ◽  
Two Dimensional ◽  
Flat Plates ◽  
Surface Loading ◽  
Confined Flow ◽  
Potential Flow Model

A potential flow model is presented for two-dimensional symmetrical bluff bodies under wall confinement. It provides a procedure for predicting surface loading on a bluff body over a range of blockage ratios. Experimental results with normal flat plates and circular cylinders for blockage ratios up to 35.5 percent substantiate the validity of the approach.

A novel potential flow model for granular flow in two-dimensional flat-bottomed packed bed with centric discharge

2019 ◽  
Vol 342 ◽  
pp. 545-554 ◽  
Author(s):  
Chengshan Wang ◽  
Xiaojing Mu ◽  
Youyou He ◽  
Dandan Li ◽  
Yanwen Shi
Keyword(s):  
Granular Flow ◽  
Potential Flow ◽  
Flow Model ◽  
Packed Bed ◽  
Two Dimensional ◽  
Potential Flow Model

Laminar separation in buoyant channel flows

1987 ◽  
Vol 177 ◽  
pp. 37-47 ◽  
Author(s):  
Vijay Modi ◽  
F. K. Moore
Keyword(s):  
Potential Flow ◽  
Flow Model ◽  
Reynolds Numbers ◽  
Large Reynolds Number ◽  
Two Dimensional ◽  
Laminar Separation ◽  
Square Root Singularity ◽  
Slow Moving ◽  
Negatively Buoyant ◽  
Potential Flow Model

A slow moving flow in a duct emerging into a quiescent negatively buoyant environment may separate from its inner wall prior to the lip. Buoyancy accelerates the flow, curving the streamlines within the duct away from the walls. The resulting deceleration at the wall may be sufficient to provoke separation. The problem of the location of this separation point in a two-dimensional channel is studied. A potential-flow model is examined first to explore the large-Reynolds-number behaviour. The form of the potential-flow description in the vicinity of the assumed location of separation is characterized by the presence of a square-root singularity in the pressure gradient at the wall. This permits use of the ideas of viscous-inviscid interaction, proposed by Sychev (1972), to determine the separation location as a function of Froude and Reynolds numbers. Results obtained in the high-Reynoldsnumber limit show that the channel flow separates at shorter distances from the entrance as Froude number is reduced.

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