基于定常射流的有车轮方背Ahmed模型主动气动减阻

Active Drag Reduction of a Square-Back Ahmed Body with Wheels Based on Steady Blowing

摘要:

近年来，主动流动控制技术已用于汽车气动减阻研究，但较多针对无车轮的简化汽车模型开展且减阻量和净节率均有待提高。本研究针对原始及带有静止、旋转车轮的方背Ahmed汽车模型，采用数值模拟方法，在模型背部施加定常射流进行主动气动减阻规律的研究。首先，分析无射流工况下车轮对方背Ahmed汽车模型气动特性的影响；其次，重点探究有车轮工况下，射流槽布置形式、射流角度、动量系数等因素对气动阻力的影响规律。获得背部射流的最佳工况为：采用连续且距边缘较近的射流槽，射流角度45°，动量系数3%，减阻量可达9.5%，对应净节率为12.7 W。

关键词:车辆工程;主动流动控制;定常射流;气动减阻;车轮;方背Ahmed模型

Abstract:

In recent years， active flow control has been applied to study the drag reduction of vehicles. However， most researches only aim at some simplified vehicle models without wheels. In addition， the amount of drag reduction and net saved energy both still need to be further improved. In this paper， based on steady blowing on the base， the active drag reduction is numerically studied on three square-back Ahmed models， i.e.，the original Ahmed model，the Ahmed model with stationary wheels， and the Ahmed model with rotating wheels， respectively. First， this paper explores in detail the effect of wheels on aerodynamic characteristics without jet flow. Then， it focuses on the influence of the form of jet groove， jet angle， and momentum coefficient on the drag under wheel conditions. It is concluded that the optimum conditions are as follows： when the form of jet groove is continuous and is close to the edge of the rear of model， the jet angle is 45° and the momentum coefficient is 3%， the corresponding drag reduction and net saved energy can reach 9.5% and 12.7W， respectively.

Key words:vehicle engineering;active flow control;steady blowing;drag reduction;wheels;square-back Ahmed model