Average windward area is an important index for calculating the trajectory, velocity attenuation and terminal effect of explosive fragments. In order to solve the problems that existing theoretical method cannot calculate windward area of irregular fragment and experiment method is not convenient for automatic calculation and has low accuracy, a Monte Carlo subdivision projection simulation algorithm is proposed. The average windward area of arbitrary shaped fragments can be obtained with coordinate translation, random rotation, plane projection, convex-hull triangulation, concave boundary searching and sorting with maximum edge length constraint, subdivision area calculation, and averaging by thousands of cycles. Results show that projection area obtained by the subdivision projection algorithm is basically the same as that obtained by software method of computer aided design. Moreover, the maximum calculation error of the algorithm is less than 7%, and its accuracy is much higher than that of the equivalent ellipsoid method. The average windward area calculated by the Monte Carlo subdivision projection simulation algorithm is consistent with theoretical formula for prefabricated fragments, and the error is less than 3%. The convergence and accuracy of the Monte Carlo subdivision projection algorithm are better than those of the icosahedral uniform orientation method.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11522433 | PMC |
http://dx.doi.org/10.1038/s41598-023-48573-9 | DOI Listing |
Sci Rep
January 2025
Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands/Dunhuang Gobi Desert Ecology and Environment Research Station, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, 730000, China.
The Desert oasis ecotone (DOE) protects the oasis from wind and sand intrusion, thereby playing a crucial role in controlling desertification. However, there is limited knowledge about how DOE functions in windproof and sand-fixation. Therefore this study employs a three-dimensional (3D) laser scanner to monitor surface accumulation and erosion, and through field observations, collects data on wind profiles, grain size, and sand transport rates to uncover the role of DOE in aeolian sand protection.
View Article and Find Full Text PDFThe present contribution documents the occurrence of Triebelina indopacifica van den Bold around Moorea and Tahiti, Windward Islands, French Polynesia and describes the new species Triebelina porinetia sp. nov..
View Article and Find Full Text PDFMaterials (Basel)
November 2024
Henan Boiler and Pressure Vessel Inspection Technology Research Institute, Zhengzhou 450045, China.
The microstructure and structure of a Super304H superheater steel pipe after 47,000 h were analyzed by metallographic microscope, scanning electron microscope (SEM), and EDS, and its mechanical properties were measured by hardness meter. The results show that the austenitic grains appear on the outer wall of Super304H steel pipe after service, while the SEM and metallographic microscope tests show that the outer wall particles are coarse. There is an obvious corrosion layer on the outer surface, and the thickness of the corrosion layer on the windward surface is significantly higher than that on the leeward surface.
View Article and Find Full Text PDFHeat Mass Transf
August 2022
Centre for Precision Engineering Material and Manufacturing Research (PEM Centre), Atlantic Technological University, Sligo, F91 YW50 Ireland.
Additive manufacturing has received significant interest in the fabrication of functional channels for heat transfer; however, the inherent rough surface finish of the additively manufactured channels can influence thermal performance. This study investigates the impact of roughness on the thermo-fluid characteristics of laminar forced convection in rough minichannels. A numerical model was developed to create 3D Gaussian roughness with specified root-mean-square height.
View Article and Find Full Text PDFYing Yong Sheng Tai Xue Bao
July 2024
CGN New Energy Holdings Co. Ltd., Beijing 100070, China.
Investigating the wind speed flow field and aerodynamic characteristics of shelterbelts with different structural features is of significant importance for the rational arrangement of shelterbelts and the mitigation of wind-blown sand disasters. Considering five cross-sectional shapes of shelterbelts (rectangle, windward right-angle triangle, leeward right-angle triangle, isosceles triangle, and parabolic) and four layout forms (single shelterbelt, L-shaped network, U-shaped network, and rectangular network), we conducted computational fluid dynamics (CFD) simulations using the large eddy simulation (LES) turbulence model to understand mean wind speed flow field and turbulence structure of shelterbelts with different structural features, and investigated the effects of shelterbelt cross-sectional shapes and layout forms on windbreak indicators, such as protection distance and area. We considered tree canopies as porous media and conducted simulation with the 'Tsujimatsu' shelterbelt in Japan with a total height () of 7 m, canopy height of 5.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!