Wind resistance aerial path planning for efficient reconstruction of offshore ship

When the unmanned aerial vehicle(UAV)is applied to three-dimensional(3D)reconstruction of the offshore ship,it faces two problems:the battery capacity limitation of the UAV and the disturbance of the wind in the environment.Wind disturbance is generally not considered in the path planning process of the existing UAV 3D reconstruction path planning research.Therefore,the planned path is only suitable for no-wind or light-wind scenarios.For the 3D reconstruction of ship targets,we propose a UAV path planning method that can satisfy both reconstruction efficiency and wind disturbance resistance requirements.Firstly,the concept of model surface complexity is proposed to generate a more efficient candidate view set.Secondly,the Min–Max strategy and a new viewpoint construction method are used to generate the initial path.Thirdly,combined with the wind field model,a method for generating a stable path against wind disturbance based on the idea of interval optimization is proposed.Experimental results demonstrate that our method can adaptively determine the number of sample points and viewpoints according to ship’s geometric characteristics and further reduce the number of viewpoints without significantly affecting the reconstruction quality;the path planned by our method is also stable against wind disturbance.

Effect of Porosity on the Wind Loads on a Hyperbolic Paraboloid Canopy Roof

A discussion is made of the wind force coefficients for designing the main wind force resisting systems of H.P. （Hyperbolic-Paraboid）-shaped porous canopy roofs on the basis of a wind tunnel experiment. Roof models with a number of small circular holes were made of nylon resin using laser lithography. The porosity was changed from 0 （solid） to 0.4. Besides the porosity, the geometric parameters of the models were the rise to span ratio and slope of the roof. The overall aerodynamic forces and moments acting on a model were measured by a six-component force balance in a turbulent boundary layer. The results indicate that the porosity significantly reduces the wind loads. The design wind force coefficients for porous canopy roofs can be provided by those for solid roofs with the same configuration multiplied by a reduction factor. The proposed wind force coefficients are verified by a comparison of the load effect predicted by the proposed wind force coefficients with the maximum load effect obtained from dynamic analyses using the time history of wind force and moment coefficients. The axial forces induced in the columns supporting the roof are regarded as the load effect for discussing the design wind loads.

Study on the Wind Erosion Resistance of Desert Soil Induced by Bacillus Megaterium

With the intensification of global climate change and the worsening of land degradation,desertification has emerged as a significant global issue threatening ecosystems and human activities.The technique of Microbial Induced Calcium Carbonate Precipitation(MICP)has been widely applied in soil stabilization and engineering geology in recent years.This study conducts experiments using Bacillus megaterium to solidify desert sand via MICP,aiming to explore its feasibility as a novel ecological method for desert protection.Experimental results indicate that desert sand treated with MICP exhibits a significant enhancement in wind erosion resistance,providing a potential solution for desert management and land restoration.

Optimal Design of the Superstructure of an Offshore Tourism Platform by Using Numerical Simulation

This paper aims to reduce the wind resistance of the self-designed offshore tourism platform by optimizing its superstructure,and a transparent shape design is finally suggested.A numerical simulation was performed to calculate the wind load on the platform to test the effect of wind resistance reduction.Two original scale models(sealed and transparent)were established in accordance with the design requirements.The numerical simulation uses the FLUENT software combined with the built-in self-compiled user-defined function(UDF).The stochastic wind was also applied on the basis of the Davenport wind spectrum.The detached eddy simulation(DES)model was used to solve the NS equation.Numerical simulation results show that the wind resistance reduction for the transparent shape model is subtle in the horizontal direction but can effectively reduce the drag force and moment in the vertical direction.Moreover,the force variation of the transparent shape model under different wind attack angles decreases,which reduces the wind load fluctuations.

Computation of bicycle wheel power

Presents the model on the drag resistance to overcome discusses the equations used for calculation of spoked and solid wheel power and force, and gives a table of power output under a certain condition for comparison of two types of wheels, and suggests a scheme to estimate power on a specific track, and the speed and the time spent on a certain track are compared to illustrate the functions of parameters.

Effect of Climate Change on Transformers Loading Conditions in the Future Smart Grid Environment

The steady-state calculations are performed using IEC guidelines to determine the hot spot temperatures of distribution and power transformers in the worst projected Finnish environment due to long summer periods. Moreover, the effect of increase in winding resistance due to increase in ambient temperatures has been taken into account. The primary objective of the research is to investigate the possible extreme circumstances due to climate change. It is concluded that the power and distribution transformers should be progressively de-rated under such circumstances for their safe operations, which will not only prove cost-effective for utilities but also improve the reliability of the power supply to their valued customers in the challenging future smart grid environment.