表面风作用下自由气球升空的数学模型与仿真

IF 0.8 Q3 ENGINEERING, AEROSPACE

Aviation Pub Date : 2022-03-23 DOI:10.3846/aviation.2022.16621

N. Daidzic

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引用次数: 0

摘要

有风条件下自由气球放飞的数学模型是基于水平轴和垂直轴上的线性动量守恒。线性动量守恒方程由一组四个非线性一阶ode表示。采用解析求解方法，对垂直加速度的非线性变系数Riccati ODE采用数值求解方法。瞬态气动升力和水平阻力是由气球包壳上的滑移流引起的。在阶跃函数响应中，自由气球需要10次半才能达到风速的90.9%。根据最小要求的包层温度，开发了一种发射条件，使净空气静力升力克服气球的惰性重量。采用微扰分析探讨净静压升力的变化。模拟了有和没有包络变形和强制对流增强冷却的情况。由于所有的气球起飞都是顺风进行的，由于空气动力升力的迅速丧失，清除障碍物成为一个问题。气球可能会停止爬升，甚至在升空后不久就开始下降，尽管强烈的加热代表着真正的危险。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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MATHEMATICAL MODEL AND SIMULATION OF FREE BALLOON LIFTOFF IN THE PRESENCE OF SURFACE WINDS

A mathematical model of free balloon launches in windy conditions is based on the conservation of the linear momentum in horizontal and vertical axes. Linear momentum conservation equations are represented by a set of four nonlinear first-order ODEs. Some ODEs were solved analytically, while the nonlinear Riccati ODE with variable coefficients for the vertical acceleration was solved using numerical ODE solvers. Transient aerodynamic lift and horizontal drag are caused by the slip flow over the balloon envelope. It takes free balloon ten half times to reach 90.9% of the wind velocity in a step function response. A launch condition was developed in terms of the minimum required envelope temperature for which the net aerostatic lift overcomes inert weight of a balloon. Perturbation analysis was used to explore changes in the net aerostatic lift. Simulations were performed to cases with and without envelope distortion and enhanced cooling due to forced convection. Since all balloon takeoffs are performed downwind, obstacle clearance becomes an issue due to rapid loss of aerodynamic lift. Balloons may stop climbing and even start descending shortly after liftoff despite intense heating representing real hazard.

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来源期刊

Aviation ENGINEERING, AEROSPACE-

CiteScore

2.40

自引率

10.00%

发文量

审稿时长

15 weeks

期刊介绍： CONCERNING THE FOLLOWING FIELDS OF RESEARCH: ▪ Flight Physics ▪ Air Traffic Management ▪ Aerostructures ▪ Airports ▪ Propulsion ▪ Human Factors ▪ Aircraft Avionics, Systems and Equipment ▪ Air Transport Technologies and Development ▪ Flight Mechanics ▪ History of Aviation ▪ Integrated Design and Validation (method and tools) Besides, it publishes: short reports and notes, reviews, reports about conferences and workshops