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Your search keyword '"Wang, Z.-W."' showing total 136 results
Start Over Author "Wang, Z.-W." Publisher iop publishing
136 results on '"Wang, Z.-W."'

5. Extreme Solar Flare-driven Short-wave Fadeout Observed by SuperDARN ZHO Radar.

Author

Liu, X. J., Wang, Z. W., Lu, J. Y., Liu, J. J., Hu, H. Q., Liu, J., Hu, Z. J., Wang, M., and Zhao, K.

Subjects
*SOLAR flares, *RADAR, *SOFT X rays, *SOVEREIGN wealth funds, *X-rays, *RADIATION, *LATITUDE
Abstract

Based on the observations from the Super Dual Auroral Radar Network at the Zhongshan Station (âˆ'74.9 MLAT, 97.2 MLON) and GOES satellites X-ray sensor, we present the first statistical study of the dayside ionospheric short-wave fadeout (SWF) events on the Southern Hemispheric high latitude from the years 2010â€"2019 and provide a normal characteristic of SWF with onset of 6 minutes 54 s, blackout of 20 minutes 24 s, and recovery of 39 minutes 36 s, respectively. All the SWF events in this work are selected to be caused by extreme flares. The statistical analysis shows both short-type and long-type SWF onset phases. Onset/blackout phase duration of long events is highly correlated with flare duration (0.79, 0.60), the SWF is mainly driven by the flare radiation profile, and the soft X-ray flux rise rate is higher for short-onset events than for most long-onset events, which is the main reason for the difference between the two types of events. In addition, the effect of ionospheric sluggishness on long-onset events also needs to be considered. The relationship between each phase’s durations of long SWFs and the effective peak X-ray flux is not obvious. However, the correlation between the integrated effective X-ray flux and the onset/blackout phase duration of long events is significant. [ABSTRACT FROM AUTHOR]

Published
2022
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21. Dynamic response of a NACA0009 hydrofoil under cavitation conditions

Author

Wang, W., Zhou, L. J., Wang, Z. W., Escaler, X., De La Torre, O., and Kang, W. Z.

Subjects
Physics::Fluid Dynamics
Abstract

The dynamic response of an hydraulic machine is greatly affected by the water due to the added mass effect. However, the presence of cavitation can change the modal response of the coupled fluid-structure system because it modifies the properties of the surrounding fluid, i.e. the speed of sound and density. In this paper, a FEM-based acoustic-fluid model has been used to simulate the dynamic response of a NACA0009 hydrofoil with attached leading edge cavitation. The natural frequencies and the corresponding mode shapes have been compared for the hydrofoil in air, in still water and in cavitation conditions. The numerical predictions show a good agreement with the experimental results obtained in a high-speed cavitation tunnel. They confirm that different fluid conditions can modify the mode shapes in comparison with the modes in air. The nodal lines of the torsion and the second bending modes are slightly shifted with water and cavitation. Furthermore, the third mode of vibration under cavitation conditions appears as a combination of the torsion and the second bending shapes. The results indicate that such alterations are mainly induced by the value of the speed of sound inside the cavity.

Published
2019

46. Enhancement of Surface Roughness and Growth Morphology of Nanoporous Anodic Alumina from Commercially Aluminum Alloy 1050 Using Two-Step Electrochemical Polishing.

Author

Chung, C. K., Tsai, C. H., and Wang, Z. W.

Subjects
SURFACE roughness, ANODIC oxidation of aluminum, ALUMINUM alloys
Abstract

This article investigates the two-step electrochemical polishing process for improving growth of nanoporous anodic aluminum oxide (AAO) from commercially low-purity (<99.5%) aluminum alloy 1050 (AA1050) at room temperature (25°C). The conventional one-step electropolishing is a vital pretreatment process before the anodic oxidation for reducing the surface roughness of high-purity (>99.99%) aluminum to promote the AAO pore structure anodized at low temperature (0-10°C). The AAO pore quality is related to the surface roughness and purity of aluminum, especially the commercial aluminum alloy is much rougher than high-purity aluminum. Moreover, the high-purity aluminum is rather expensive and of low strength for practical application. Here, we propose a novel two-step electropolishing approach to improve the anodization of low-cost commercial AA1050 alloy with low purity and high roughness. The optimum electrolyte ratio and polishing time of the two-step electropolishing can effectively achieve the smooth surface for promoting AAO growth. The pore size distribution and deviation of AAO from AA1050 at 25°C are enhanced from 17.1 ± 4.90 nm with 15.62% max distribution (one-step electropolishing) to 23.5 ± 3.74 nm with 19.35% max distribution (two-step electropolishing) at stable time-dependent current evolution. [ABSTRACT FROM AUTHOR]

Published
2018
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