Numerical simulation and experiments of ground-based laser irradiating small scale space debris

Optik ◽  
2016 ◽  
Vol 127 (3) ◽  
pp. 1078-1083 ◽  
Author(s):  
Yingwu Fang ◽  
Liwei Yang ◽  
Shanghong Zhao ◽  
Yi Wang
Optik ◽  
2017 ◽  
Vol 141 ◽  
pp. 105-113 ◽  
Author(s):  
Quan Wen ◽  
Liwei Yang ◽  
Shanghong Zhao ◽  
Yingwu Fang ◽  
Yi Wang

2020 ◽  
Vol 51 (1) ◽  
pp. 1-5
Author(s):  
Yingwu Fang

The aim of this article was to address the de-orbit behaviors of space-based laser driving small scale space debris in low earth orbit (LEO) based on different orbit and laser parameters in coplanar/non-coplanar conditions. The de-orbit model of space-based laser irradiating small scale space debris was established, the de-orbit rules of irradiation angle and irradiation distance with action time in different orbital inclination and right ascension of the ascending node (RAAN) were investigated by numerical simulations, and the change rules of the perigee altitude with the number of laser pulses were discussed in different orbital inclination and RAAN. As a result, the clearance window of removing small scale space debris was described in detail. These results of numerical simulations will provide theoretical guide for designing clear schemes and selecting efficient parameters.


2016 ◽  
Vol 45 (2) ◽  
pp. 0229002 ◽  
Author(s):  
方英武 Fang Yingwu ◽  
赵尚弘 Zhao Shanghong ◽  
杨丽薇 Yang Liwei ◽  
王轶 Wang Yi ◽  
楚兴春 Chu Xingchun ◽  
...  
Keyword(s):  

2016 ◽  
Vol 45 (2) ◽  
pp. 229002
Author(s):  
方英武 Fang Yingwu ◽  
赵尚弘 Zhao Shanghong ◽  
杨丽薇 Yang Liwei ◽  
王轶 Wang Yi ◽  
楚兴春 Chu Xingchun ◽  
...  
Keyword(s):  

Optik ◽  
2018 ◽  
Vol 154 ◽  
pp. 83-92 ◽  
Author(s):  
Quan Wen ◽  
Liwei Yang ◽  
Shanghong Zhao ◽  
Yingwu Fang ◽  
Yi Wang ◽  
...  

2018 ◽  
Vol 39 (2) ◽  
pp. 114-118
Author(s):  
Yang Liwei ◽  
Wen Quan ◽  
Zhao Shanghong ◽  
Fang Yingwu ◽  
Wang Yi ◽  
...  

2015 ◽  
Vol 764 ◽  
pp. 362-394 ◽  
Author(s):  
T. Dairay ◽  
V. Fortuné ◽  
E. Lamballais ◽  
L.-E. Brizzi

AbstractDirect numerical simulation (DNS) of an impinging jet flow with a nozzle-to-plate distance of two jet diameters and a Reynolds number of 10 000 is carried out at high spatial resolution using high-order numerical methods. The flow configuration is designed to enable the development of a fully turbulent regime with the appearance of a well-marked secondary maximum in the radial distribution of the mean heat transfer. The velocity and temperature statistics are validated with documented experiments. The DNS database is then analysed focusing on the role of unsteady processes to explain the spatial distribution of the heat transfer coefficient at the wall. A phenomenological scenario is proposed on the basis of instantaneous flow visualisations in order to explain the non-monotonic radial evolution of the Nusselt number in the stagnation region. This scenario is then assessed by analysing the wall temperature and the wall shear stress distributions and also through the use of conditional averaging of velocity and temperature fields. On one hand, the heat transfer is primarily driven by the large-scale toroidal primary and secondary vortices emitted periodically. On the other hand, these vortices are subjected to azimuthal distortions associated with the production of radially elongated structures at small scale. These distortions are responsible for the appearance of very high heat transfer zones organised as cold fluid spots on the heated wall. These cold spots are shaped by the radial structures through a filament propagation of the heat transfer. The analysis of probability density functions shows that these strong events are highly intermittent in time and space while contributing essentially to the secondary peak observed in the radial evolution of the Nusselt number.


Author(s):  
Junnosuke Okajima ◽  
Atsuki Komiya ◽  
Shigenao Maruyama

The objective of this work is to experimentally and numerically evaluate small-scale cryosurgery using an ultrafine cryoprobe. The outer diameter (OD) of the cryoprobe was 550 μm. The cooling performance of the cryoprobe was tested with a freezing experiment using hydrogel at 37 °C. As a result of 1 min of cooling, the surface temperature of the cryoprobe reached −35 °C and the radius of the frozen region was 2 mm. To evaluate the temperature distribution, a numerical simulation was conducted. The temperature distribution in the frozen region and the heat transfer coefficient was discussed.


2005 ◽  
Vol 14 (5) ◽  
pp. 580-596 ◽  
Author(s):  
Simon Lessels ◽  
Roy A. Ruddle

Two experiments investigated participants' ability to search for targets in a cluttered small-scale space. The first experiment was conducted in the real world with two field of view conditions (full vs. restricted), and participants found the task trivial to perform in both. The second experiment used the same search task but was conducted in a desktop virtual environment (VE), and investigated two movement interfaces and two visual scene conditions. Participants restricted to forward only movement performed the search task quicker and more efficiently (visiting fewer targets) than those who used an interface that allowed more flexible movement (forward, backward, left, right, and diagonal). Also, participants using a high fidelity visual scene performed the task significantly quicker and more efficiently than those who used a low fidelity scene. The performance differences among all the conditions decreased with practice, but the performance of the best VE group approached that of the real-world participants. These results indicate the importance of using high fidelity scenes in VEs, and suggest that the use of a simple control system is sufficient for maintaining one's spatial orientation during searching.


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