高超声速飞行器复杂外形转捩预测

Transition Predictions of Hypersonic Complex Configuration

采用k-ω-γ转捩模式对某新型飞行器外形的典型流动特征和边界层失稳特性进行了分析.研究结果表明,横流是影响飞行器大面积转捩的主要因素.随着高度增加,来流Reynolds数减小,迎风面和背风面的转捩起始位置均向下游移动.随着攻角增加,头部附近背风面的展向压力梯度增大,横流效应增强,转捩起始位置向上游移动;另一方面攻角增加导致头部激波增强,波后迎风面密度显著增大,边界层外缘Reynolds数增大,导致迎风面转捩提前发生.0°攻角下背风面中心线附近由压缩面诱导的流动分离导致转捩提前,产生“凸”字型转捩型线,5°攻角时该流动分离发生于转捩之后,“凸”字型转捩型线消失.

The k-ω-γtransition model is used to analyze the typical flow characteristics and boundary layer instability characteristics of a new aircraft configuration.The results indicate that the existence of cross flow is the main factor affecting large area transition of the aircraft.As the height increases,the Reynolds number decreases,and the transition onsets of windward and leeward move downstream.As the angle of attack increases,the spanwise pressure gradient on the leeward side near the head increases,the cross-flow effect is enhanced,and the transition onset moves upstream.At the same time,the head shock wave is enhanced,and the density on the windward side behind the wave increases significantly,and the Reynolds number at the outer edge of the boundary layer increases,which leads to an earlier transition on the windward side.At 0°angle of attack,the flow separation induced by the compression surface leads to an early transition near the centerline of the leeward surface,resulting in a″convex″transition profile.At 5°angle of attack,the flow separation occurs after the transition,and the″convex″transition profile disappears.