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In this paper, the natural supercavitys are studied both experimentally and numerically. A series of supercavitating vehicle water-entry test are carried out at different speeds, where it is found that the minimum pressure in the cavity gradually reduced with the increase of water-entry speed. The cause for the evolution progress of natural supercavitation is difficult to get from the experiment,...
Unmanned Aerial Vehicles (UAVs) are used in all kinds of applications. The utilization of multiple UAVs acting in a cooperative manner within the same operation field is especially interesting. However, many deployment scenarios pose the challenge of continuous applications. UAVs are equipped with a limited battery which enables short term applications. Replacement and recharging maintenance processes...
Dynamical technical networks and dynamic network objects (DNO) as a special case of them are considered in many subject areas as objects of research, design, quality assurance, automatization, monitoring and control. In this paper we focus on the simulation of the mine air networks (MAN) as an example of dynamic network objects with distributed parameters. To improve the simulation process, we propose...
Renewable source of energy has lots of relevance today. Solar energy is available in abundance and it is preferable because it is pollution free and there is no cost attached to it. However solar energy is not reliable in nature because its production depends upon weather condition, time of the day and other local parameters. If a consumer have accurate prediction of solar power, the trade-off with...
This paper proposes the use of a Numerical Weather Prediction (NWP) model to emulate site diversity statistics. Particularly, the Weather Research and Forecasting (WRF) model coupled with an Electromagnetic Module (EMM) is used here to generate rain attenuation time series in four sites in south of France. Rain attenuation statistics derived from WRF simulations are then compared to experimental propagation...
In this paper, an improved changing-topology moving mesh method is developed in OpenFOAM (a widely used CFD software) to solve the moving boundary problem. We use mesh smoothing and edge swapping to improve the mesh quality, together with edge bisection and edge contraction to control the mesh resolution. In order to increase the mesh motion efficiency, a local refinement algorithm is realized. In...
Some extensive numerical simulations of the atmospheric composition fields in the city of Sofia have been recently performed and an ensemble, comprehensive enough as to provide statistically reliable assessment of the atmospheric composition climate of Sofia — typical and extreme features of the special/temporal behavior, annual means and seasonal variations, etc. has been constructed. The simulations...
The article is focused on dynamic modeling and simulation of pulmonary compartment behaving and response during gas flowing in the lungs. Dynamical simulations based on the differential equations represent time-depended models describing dynamic state of individual gases in the lungs and other tissues. The pulmonary system model includes the two ways: derivation of mathematical model for individual...
A three-dimensional particle model to describe the moisture distribution in copra for 20 hours of drying was developed using computational fluid dynamics. Drying experiments were performed for seven different temperatures in the range of 45 – 75 degrees of Celsius in a laboratory scale hot air dryer using copra samples of the dimensions 0.01×0.01×0.01 m3. Results of the spatial moisture distribution...
In this work, a parametric electromagnetic (EM) modelling to develop Textile Integrated Circuits (TIC) is presented. Due to the necessity of having an accurate model to design TIC, avoiding the simulation of every filament which forms each yarn, a three-step characterisation of textile structures has been carried out. First, an ideal non-deformed model of the textile structure is represented, taking...
Data centres account for approx. 1.3% of the world's electricity consumption, of which up to 50% of that power is dedicated to keeping the actual equipment cool. This represents a huge opportunity to reduce data centre energy consumption by tackling the cooling system operations with a focus on thermal management. This work presents a novel Data Centre Air Flow Model (DCAM) for temperature prediction...
The performance of our FDTD code is analyzed in two HPC systems. A reverberation chamber is fully simulated and the statistical analysis reveals how the introduction of hemisphere scatters improves the chaotic nature of the random electromagnetic fields generated by the cavity, with particular emphasis on low frequencies.
Swirling flow in gas turbine combustors is a very common tradition in aerospace and/or industrial applications. This is because, swirl flows help to anchor flames, and cause better air-fuel mixing which enhance combustion efficiency and reduce harmful emissions. As a result, it is of a high interest to be able to predict the behavior of swirling turbulent flows in order to better design combustors...
The prediction of cross-flow instabilities transition phenomenon is difficult to be combined with modern CFD parallel computation. To solve this problem, on the basis of SA-γ-Reθt transition model, a new transition model is presented here, which solves cross-flow displacement thickness Reynolds number locally using three-dimentional boundary layer similar solution and also sets cross-flow instabilities...
Air Data Computer (ADC) is an electronics device computes air data flight parameters. The objective of this paper is to analyze, simulate, and propose hardware implementation module for the Air Data Computer. Simulation of ADC model has been faced by two problems. The first one was to choose true values of dynamic temperature because it depends on flight altitude and airspeed. The second problem is...
In solving various kinds of problems detect and determine elevation of coordinates of air targets requires modelling of the underlying surface for breeding secondarily emitted from the target of the probing signal. For this, you need to deduce the dependence, bind the elevation of the target with a radar portrait derived from the underlying surface.
The Cyber-Physical System has been characterized by deep integration of computing process and physical process, heterogeneous composition, etc. So it is difficult to model Cyber-Physical System and to analyze its properties. An approach to model Cyber-Physical System and to analyze its safety based on multiple modeling languages transformation is put forward. We model the Cyber-Physical System by...
Gas-liquid systems form a key component of many chemical industry processes. In such systems, the knowledge of the gas volume fraction, its distribution and its eventual effect on mass transfer and reactions is absolutely essential. Experimental measurements have allowed to look into such systems to a good level of details, resulting in numerous correlations, which are commonly used in the design...
Variable-fidelity (VF) approximation models are wildly used to replace computational expensive simulation models in complex engineering designs. In this paper, a design space reduction variable-fidelity metamodeling (DSR-VFM) approach is proposed. In the proposed DSR-VFM, addition scaling Kriging (ASK) is chosen as the approximation model and self-organizing maps (SOM) is adopt to reduce the design...
Several numerical models were adopted to simulate the flow behavior inside an oscillating column OWC device. The current paper presents a comparison between two numerical models, the prime is based on the study of the air flow in a simplified OWC piston model, and the other takes into consideration the whole domain composed of the OWC chamber coupled with a wave tank WT; which enable to investigate...
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