STUDY ON UNCERTAINTY OF TSUNAMI DEBRIS MOTION BY INITIAL ARRANGMENT UNCERTAINTY IN DRIFT MOTION

2021 ◽  
Vol 77 (2) ◽  
pp. I_313-I_318
Author(s):  
Riko MORITA ◽  
Masashi WATANABE ◽  
Taro ARIKAWA
Keyword(s):  
Drift Motion

Analysis of the First Order and Slowly Varying Motions of an Axisymmetric Floating Body in Bichromatic Waves

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
João Pessoa ◽  
Nuno Fonseca ◽  
C. Guedes Soares
Keyword(s):  
Vertical Cylinder ◽  
Vertical Axis ◽  
Second Order ◽  
The Body ◽  
Floating Body ◽  
Drift Motion ◽  
First Order ◽  
Motion Responses ◽  
Simple Geometry ◽  
Good Agreement

The paper presents an experimental and numerical investigation on the motions of a floating body of simple geometry subjected to harmonic and biharmonic waves. The experiments were carried out in three different water depths representing shallow and deep water. The body is axisymmetric about the vertical axis, like a vertical cylinder with a rounded bottom, and it is kept in place with a soft mooring system. The experimental results include the first order motion responses, the steady drift motion offset in regular waves and the slowly varying motions due to second order interaction in biharmonic waves. The hydrodynamic problem is solved numerically with a second order boundary element method. The results show a good agreement of the numerical calculations with the experiments.

Analysis on the Performance of Deckwetness of Sandglass-type and Cylindrical Floating Bodies

2016 ◽  
Vol 60 (03) ◽  
pp. 145-155
Author(s):  
Ya-zhen Du ◽  
Wen-hua Wang ◽  
Lin-lin Wang ◽  
Yu-xin Yao ◽  
Hao Gao ◽  
...  
Keyword(s):  
Transfer Functions ◽  
Linear Response Theory ◽  
Second Order ◽  
Irregular Waves ◽  
Wave Loads ◽  
Floating Bodies ◽  
Drift Motion ◽  
First Order ◽  
Series Of Experiments ◽  
Deck Wetness

In this paper, the influence of the second-order slowly varying loads on the estimation of deck wetness is studied. A series of experiments related to classic cylindrical and new sandglass-type Floating Production, Storage, and Offloading Unit (FPSO) models are conducted. Due to the distinctive configuration design, the sand glass type FPSO model exhibits more excellent deck wetness performance than the cylindrical one in irregular waves. Based on wave potential theory, the first-order wave loads and the full quadratic transfer functions of second-order slowly varying loads are obtained by the frequency-domain numerical boundary element method. On this basis, the traditional spectral analysis only accounting for the first-order wave loads and time-domain numerical simulation considering both the first-order wave loads and nonlinear second-order slowly varying wave loads are employed to predict the numbers of occurrence of deck wetness per hour of the two floating models, respectively. By comparing the results of the two methods with experimental data, the shortcomings of traditional method based on linear response theory emerge and it is of great significance to consider the second-order slowly drift motion response in the analysis of deck wetness of the new sandglass-type FPSO.

Drift Motion

1972 ◽  
pp. 68-70
Author(s):  
D. A. Frank-Kamenetskii
Keyword(s):  
Drift Motion

Transient cusp ionospheric disturbances caused by a solar wind dynamic pressure enhancement

2021 ◽  
Author(s):  
Jianjun Liu
Keyword(s):  
Plasma Flow ◽  
Dynamic Pressure ◽  
Geomagnetic Disturbance ◽  
Flow Reversal ◽  
Drift Motion ◽  
Zhongshan Station ◽  
Shock Impingement ◽  
Field Aligned Current ◽  
Convection Patterns ◽  
The Antarctic

<p>Interplanetary (IP) shock driven sudden compression produces disturbances in the polar ionosphere. Various studies have investigated the effects of IP shock using imagers and radars. However, very few studies have reported the plasma flow reversal and a sudden vertical plasma drift motion following a CME driven IP shock. We report on the cusp ionospheric features following an IP shock impingement on 16 June 2012, using SuperDARN radar and digisonde from the Antarctic Zhongshan Station (ZHO). SuperDARN ZHO radar observed instant strong plasma flow reversal during the IP shock driven sudden impulse (SI) with a suppression in the number of backscatter echoes. Besides, we also report on a “Doppler Impulse” phenomenon, an instant and brief downward plasma motion, were observed by the digisonde in response to the SI and discuss the possible physical causes. Geomagnetic disturbance and convection patterns indicate the flow reversal was generated by the downward field-aligned current (FAC). We speculate that sudden enhancement in ionization associated with SI is responsible for generating the Doppler Impulse phenomenon.</p>

scholarly journals The Effect of the Second-Order Wave Loads on Drift Motion of a Semi-Submersible Floating Offshore Wind Turbine

2020 ◽  
Vol 8 (11) ◽  
pp. 859
Author(s):  
Thanh-Dam Pham ◽  
Hyunkyoung Shin
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Second Order ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wave Loads ◽  
Hydrodynamic Loads ◽  
Drift Motion ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines

Floating offshore wind turbines (FOWTs) have been installed in Europe and Japan with relatively modern technology. The installation of floating wind farms in deep water is recommended because the wind speed is stronger and more stable. The design of the FOWT must ensure it is able to withstand complex environmental conditions including wind, wave, current, and performance of the wind turbine. It needs simulation tools with fully integrated hydrodynamic-servo-elastic modeling capabilities for the floating offshore wind turbines. Most of the numerical simulation approaches consider only first-order hydrodynamic loads; however, the second-order hydrodynamic loads have an effect on a floating platform which is moored by a catenary mooring system. At the difference-frequencies of the incident wave components, the drift motion of a FOWT system is able to have large oscillation around its natural frequency. This paper presents the effects of second-order wave loads to the drift motion of a semi-submersible type. This work also aimed to validate the hydrodynamic model of Ulsan University (UOU) in-house codes through numerical simulations and model tests. The NREL FAST code was used for the fully coupled simulation, and in-house codes of UOU generates hydrodynamic coefficients as the input for the FAST code. The model test was performed in the water tank of UOU.

Photothermoelectric resistance effect observed in Ti/SiO2/Si structure induced by 10.6 μm CO2 laser

2020 ◽  
Vol 34 (34) ◽  
pp. 2050391
Author(s):  
Xu Sun ◽  
Pengfei Zhu ◽  
Kun Zhu ◽  
Yunxia Ping ◽  
Chaomin Zhang ◽  
...  
Keyword(s):  
Thermal Resistance ◽  
Motion Direction ◽  
Change Rate ◽  
Continuous Irradiation ◽  
Drift Motion ◽  
Diffusion Motion ◽  
Si Films ◽  
Value Changes ◽  
And Diffusion ◽  
Resistance Value

A novel photothermoelectric resistance effect of the Ti/SiO2/Si films induced by 10.6 [Formula: see text]m CO2 laser is discovered and investigated. The transient response of the resistance is observed and analyzed in this work. Under the continuous irradiation of the laser, the thermal resistance value changes with the irradiating time and gradually reaches a stable saturation. The results indicate that the rise time of thermal resistance is shortened and its change rate increased as laser power gets higher. The inner battery of the ohmmeter exerts the positive or negative bias voltage, causing the diffusion motion direction of the hot electrons to be opposite or the same direction with the drift motion, which can increase or decrease the thermal resistance value. Those experimental phenomena are explained by the drift and diffusion motion of the electrons. Based on the results, the Ti/SiO2/Si structure is an attractive candidate for thermal effect devices.

Sign in / Sign up

Export Citation Format

Share Document