NUMERICAL STUDY ON THE HIGH-SPEED WATER-ENTRY BEHAVIORS OF CYLINDRICAL, HEMISPHERICAL AND CONICAL PROJECTILES

2009 ◽  
Author(s):  
Zitao Guo ◽  
Wei Zhang ◽  
Shuping Luan ◽  
Xinke Xiao ◽  
Mark Elert ◽  
...  
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
Water Entry

Numerical study of impact force and ricochet behavior of high speed water-entry bodies

2003 ◽  
Vol 32 (7) ◽  
pp. 939-951 ◽  
Author(s):  
Man-Sung Park ◽  
Young-Rae Jung ◽  
Warn-Gyu Park
Keyword(s):  
High Speed ◽  
Impact Force ◽  
Numerical Study ◽  
Water Entry

scholarly journals Experimental and Numerical Study of Water Entry Supercavity Influenced by Turbulent Drag-Reducing Additives

2014 ◽  
Vol 6 ◽  
pp. 280643 ◽  
Author(s):  
Chen-Xing Jiang ◽  
Feng-Chen Li
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
High Speed ◽  
Numerical Study ◽  
Ccd Camera ◽  
Water Entry ◽  
Multiphase Model ◽  
Turbulent Drag ◽  
Unsteady Rans ◽  
Simulation Results

The configurational and dynamic characteristics of water entry supercavities influenced by turbulent drag-reducing additives were studied through supercavitating projectile approach, experimentally and numerically. The projectile was projected vertically into water and aqueous solution of CTAC with weight concentrations of 100, 500, and 1000 ppm, respectively, using a pneumatic nail gun. The trajectories of the projectile and the supercavity configuration were recorded by a high-speed CCD camera. Besides, water entry supercavities in water and CTAC solution were numerically simulated based on unsteady RANS scheme, together with application of VOF multiphase model. The Cross viscosity model was adopted to represent the fluid property of CTAC solution. It was obtained that the numerical simulation results are in consistence with experimental data. Numerical and experimental results all show that the length and diameter of supercavity in drag-reducing solution are larger than those in water, and the drag coefficient is smaller than that in water; the maintaining time of supercavity is longer in solution as well. The surface tension plays an important role in maintaining the cavity. Turbulent drag-reducing additives have the potential in enhancement of supercavitation and drag reduction.

Thermal comfort analysis of a high-speed train cabin considering the solar radiation effects

2019 ◽  
Vol 29 (8) ◽  
pp. 1101-1117
Author(s):  
Lin Yang ◽  
Xiangdong Li ◽  
Jiyuan Tu
Keyword(s):  
Solar Radiation ◽  
Thermal Comfort ◽  
High Speed ◽  
Radiation Effects ◽  
Numerical Study ◽  
Thermal Conditions ◽  
Long Distance ◽  
High Speed Rail ◽  
Hot Weather ◽  
Cabin Environment

Due to the fast development of high-speed rail (HSR) around the world, high-speed trains (HSTs) are becoming a strong competitor against airliners in terms of long-distance travel. Compared with airliner cabins, HST cabins have much larger window sizes. When the big windows provide better lighting and view of the scenery, they also have significant effects on the thermal conditions in the cabins due to the solar radiation through them. This study presents a numerical study on the solar radiation on the thermal comfort in a typical HST cabin. The effect of solar radiation was discussed in terms of airflow pattern, temperature distribution and thermal comfort indices. Parametric studies with seven different daytime hours were carried out. The effect of using the roller curtain was also studied. The overall cabin air temperature, especially near passengers, was found to have significantly increased by solar radiation. Passengers sitting next to windows were recorded to have an obvious thermal comfort variation at different hours of the day. To improve the passengers’ comfort and reduce energy consumption during hot weather, the use of a curtain could effectively reduce the solar radiation effect in the cabin environment.

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