民机上翘后体绕流流型的实验研究

An experimental study of flow patterns over the upswept after-body of a civil aircraft

针对民机上翘后体绕流特性为研究目标,在D 1风洞应用油流显示、空间烟线显示、烟线/激光片光显示和测压等多种实验手段,着重研究在不同迎角下,上翘角对后体分离流型的影响。显示实验结果表明随着模型由负迎角向正迎角改变,后体流型按照物面油流图画的表现形式分为上主分离线流型、无主分离线流型和下主分离线流型,对应的空间涡系则称为下涡系、无涡系和上涡系。在相同的迎角下上翘角大的后体分离强于上翘角小的后体。上翘角的存在引起的后体局部迎角改变是上涡系和下涡系产生机理不同的根本原因。

The purpose is to study the flow characteristics over the upswept afterbody of a civil aircraft. The test is conducted in the D1 wind tunnel through the met hods of oil flow, smokewire flow, smokewire/laser sheet display and pressure measurement to investigate the rules of the separation flow on the afterbody with different upswept angles in different attack angles. When the attack angles change from negative angle to positive angle, the flow types over the afterbo dy can be divided into upseparated line type, nonseparated line type and und erseparated line type according to the map of oil flow, and the corresponding vortices are called undervortex, nonvortex and upvortex. The separation on an afterbody with higher upswept angle is stronger than the lower one. The re ason of the difference between upvortex and undervortex is the change of loc al attack angle on the afterbody caused by the existence of upswept angle. 