On the Jet Curtain Over Water

1982 ◽  
Vol 26 (02) ◽  
pp. 77-88
Author(s):  
D. S. Tselnik
Keyword(s):  
Simple Model ◽  
Water Surface ◽  
Vertical Axis ◽  
Two Dimensional ◽  
Flow Mechanism ◽  
Air Jet ◽  
Air Cushion ◽  
Special Case ◽  
Weightless Fluid ◽  
Jet Curtain

The problem of two planar or two-dimensional jets of nonviscous, incompressible, weightless fluid flowing from two nozzles installed symmetrically with respect to a vertical axis onto the surface of an immobile heavy liquid is considered. The flow pattern represents a simple model of a jet curtain of an air-cushion vehicle. The complete theoretical solution to the problem is found—in a thin-jet approximation and under the assumption that the height of the nozzles with respect to the undisturbed surface of the liquid is fixed. The special case of a single nozzle is also considered. Some experimental observations of an air jet flowing from an individual slotted nozzle onto a water surface are presented, and an explanation of the flow mechanism is proposed for the vertical nozzle. In essence, the corresponding process of flow has to be random.

The Second-Order Theory of Heaving Cylinders in a Free Surface

1968 ◽  
Vol 12 (04) ◽  
pp. 313-327
Author(s):  
Choung Mook Lee
Keyword(s):  
Free Surface ◽  
Water Surface ◽  
Vertical Axis ◽  
Order Theory ◽  
Second Order ◽  
The Body ◽  
Two Dimensional ◽  
Forced Motion ◽  
Axis Of Symmetry ◽  
The Waves

A second-order potential solution is sought for a two-dimensional symmetric cylinder placed horizontally in a free surface and forced to oscillate vertically. The forced motion is simple harmonic, and the amplitude is small compared to the beam of the cylinder. The resulting potential-theory problem is solved by placing singularities of all orders at the intersection of the water surface at rest with the vertical axis of symmetry, and by determining their strengths from the boundary condition on the body. The pressure distribution on the cylinder, the force acting upon it, and the waves generated by it are derived through the second order. Numerical computations are made for a circular cylinder and for a U-shaped cylinder, and the results are presented in graphs.

TWO-DIMENSIONAL SIMULATION OF STEAM-AIR JET CONDENSED INTO SUBCOOLED WATER

2018 ◽  
Author(s):  
Haibo Li ◽  
Maocheng Tian ◽  
Xiaohang Qu ◽  
Min Wei
Keyword(s):  
Two Dimensional ◽  
Subcooled Water ◽  
Air Jet ◽  
Dimensional Simulation

scholarly journals Onset of Convection in Two-Dimensional Porous Cavities with Open and Conducting Boundaries

2021 ◽  
Vol 136 (3) ◽  
pp. 791-812
Author(s):  
Peder A. Tyvand ◽  
Jonas Kristiansen Nøland
Keyword(s):  
Critical Rayleigh Number ◽  
Numerical Results ◽  
Temperature Perturbation ◽  
Two Dimensional ◽  
Onset Of Convection ◽  
Order Problem ◽  
Fourth Order Problem ◽  
Thermally Conducting ◽  
Perturbation Pressure ◽  
Special Case

AbstractThe onset of thermal convection in two-dimensional porous cavities heated from below is studied theoretically. An open (constant-pressure) boundary is assumed, with zero perturbation temperature (thermally conducting). The resulting eigenvalue problem is a full fourth-order problem without degeneracies. Numerical results are presented for rectangular and elliptical cavities, with the circle as a special case. The analytical solution for an upright rectangle confirms the numerical results. Streamlines penetrating the open cavities are plotted, together with the isotherms for the associated closed thermal cells. Isobars forming pressure cells are depicted for the perturbation pressure. The critical Rayleigh number is calculated as a function of geometric parameters, including the tilt angle of the rectangle and ellipse. An improved physical scaling of the Darcy–Bénard problem is suggested. Its significance is indicated by the ratio of maximal vertical velocity to maximal temperature perturbation.

scholarly journals A Fast Two-Dimensional Numerical Method for the Wake Simulation of a Vertical Axis Wind Turbine

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 49
Author(s):  
Zheng Yuan ◽  
Jin Jiang ◽  
Jun Zang ◽  
Qihu Sheng ◽  
Ke Sun ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Numerical Method ◽  
Three Dimensional ◽  
Particle Method ◽  
Vortex Method ◽  
Vertical Axis ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Wake Effect ◽  
Array Design

In the array design of the vertical axis wind turbines (VAWT), the wake effect of the upstream VAWT on the downstream VAWT needs to be considered. In order to simulate the velocity distribution of a VAWT wake rapidly, a new two-dimensional numerical method is proposed, which can make the array design easier and faster. In this new approach, the finite vortex method and vortex particle method are combined to simulate the generation and evolution of the vortex, respectively, the fast multipole method (FMM) is used to accelerate the calculation. Based on a characteristic of the VAWT wake, that is, the velocity distribution can be fitted into a power-law function, a new correction model is introduced to correct the three-dimensional effect of the VAWT wake. Finally, the simulation results can be approximated to the published experimental results in the first-order. As a new numerical method to simulate the complex VAWT wake, this paper proves the feasibility of the method and makes a preliminary validation. This method is not used to simulate the complex three-dimensional turbulent evolution but to simulate the velocity distribution quickly and relatively accurately, which meets the requirement for rapid simulation in the preliminary array design.

Separation of Enantiomers and Racemate Formation in Two-Dimensional Crystals at the Water Surface from Racemic α-Amino Acid Amphiphiles:  Design and Structure

1997 ◽  
Vol 119 (5) ◽  
pp. 933-942 ◽  
Author(s):  
Isabelle Weissbuch ◽  
Maria Berfeld ◽  
Wim Bouwman ◽  
Kristian Kjaer ◽  
Jens Als-Nielsen ◽  
...  
Keyword(s):  
Amino Acid ◽  
Water Surface ◽  
Two Dimensional ◽  
Separation Of Enantiomers
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