Unsteady characteristics of tsunami flow propagating over a land after overtopping seawall

2014 ◽  
pp. 615-621
Author(s):  
H Shirai ◽  
T Hosoda
Keyword(s):  
Unsteady Characteristics

scholarly journals Investigation of Pressure Oscillation and Cavitation Characteristics for Submerged Self-Resonating Waterjet

2021 ◽  
Vol 11 (15) ◽  
pp. 6972
Author(s):  
Lihua Cui ◽  
Fei Ma ◽  
Tengfei Cai
Keyword(s):  
Sudden Change ◽  
Three Dimensional ◽  
Pressure Oscillation ◽  
Experimental Tests ◽  
Low Pressure ◽  
The Self ◽  
Two Phase ◽  
Cavitation Phenomenon ◽  
Pressure Zone ◽  
Unsteady Characteristics

The cavitation phenomenon of the self-resonating waterjet for the modulation of erosion characteristics is investigated in this paper. A three-dimensional computational fluid dynamics (CFD) model was developed to analyze the unsteady characteristics of the self-resonating jet. The numerical model employs the mixture two-phase model, coupling the realizable turbulence model and Schnerr–Sauer cavitation model. Collected data from experimental tests were used to validate the model. Results of numerical simulations and experimental data frequency bands obtained by the Fast Fourier transform (FFT) method were in very good agreement. For better understanding the physical phenomena, the velocity, the pressure distributions, and the cavitation characteristics were investigated. The obtained results show that the sudden change of the flow velocity at the outlet of the nozzle leads to the forms of the low-pressure zone. When the pressure at the low-pressure zone is lower than the vapor pressure, the cavitation occurs. The flow field structure of the waterjet can be directly perceived through simulation, which can provide theoretical support for realizing the modulation of the erosion characteristics, optimizing nozzle structure.

Numerical Investigation on Unsteady Characteristics in Different Rim Seal Geometries: Part A

2021 ◽  
Author(s):  
Lei Xie ◽  
Ruonan Wang ◽  
Guang Liu ◽  
Qiang Du ◽  
Zengyan Lian
Keyword(s):  
Numerical Investigation ◽  
Unsteady Characteristics

Unsteady Tip Leakage Vortex Cavitation Originating From the Tip Clearance of an Oscillating Hydrofoil

2005 ◽  
Vol 128 (3) ◽  
pp. 421-429 ◽  
Author(s):  
Masahiro Murayama ◽  
Yoshiki Yoshida ◽  
Yoshinobu Tsujimoto
Keyword(s):  
Steady State ◽  
Qualitative Agreement ◽  
Cavity Growth ◽  
Simple Calculation ◽  
Tip Clearance ◽  
Cavity Volume ◽  
Cavity Size ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Unsteady Characteristics

Tip leakage vortex cavitations originating from the tip clearance of an oscillating hydrofoil were observed experimentally. It was found that the delay between the unsteady and the steady-state results of the tip leakage vortex cavitation increase, and that the maximum cavity size decreases when the reduced oscillating frequency increases. To simulate the unsteady characteristics of tip leakage vortex cavitation, a simple calculation based on slender body approximation was conducted taking into account the effect of cavity growth. The calculation and experimental results of the cavity volume fluctuation were found to be in qualitative agreement.

Porous Wall Gas Lubricated Journal Bearings: Theoretical Investigation

1979 ◽  
Vol 101 (4) ◽  
pp. 458-465 ◽  
Author(s):  
E. P. Gargiulo
Keyword(s):  
Experimental Investigation ◽  
Dynamic Stiffness ◽  
Porous Wall ◽  
Companion Paper ◽  
Journal Bearings ◽  
Damping Properties ◽  
Governing Equations ◽  
Performance Curves ◽  
Unsteady Characteristics ◽  
Stiffness And Damping

A model has been developed to compute the dynamic stiffness and damping properties of externally pressurized, porous-wall, gas journal bearings which includes the effects of journal rotation and eccentricity. This paper presents the derivation of the governing equations and the perturbation analysis used to find the unsteady characteristics. Typical nondimensional performance curves are found and the influences of seven governing parameters are discussed. A companion paper describes an experimental investigation of porous journal bearings.

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