%0 Journal Article
%T STABILITY ANALYSIS ON SUPERSONICTRAILING-LINE VORTEX<br>超声速尾涡的稳定性分析
%A Wei Mingjun
%A Sun Dejnn
%A Yin Xieyuan
%A <br>魏明骏
%A 孙德军
%A 尹协远
%A 吴介之
%J 力学学报
%D 1999
%I 
%X In recent years there has been a great deal of interests in the stability of swirlingflows. It is because of not only the significance to the enhancement of supersonic mixing butalso the important applications to many practical flows such as the trailing-line vortices behindan aircraft. The absolute/convective instability of incompressible swirling flows and the temporalinstability of compressible swirling flows have been fully explored, whereas the absolute/convectiveinstability of compressible swirling flows remains nuclear. In this paper, the absolute/convectiveinstability of a supersonic trailing-line vortex is studied for the first time. The normal modemethod is applied to linearized N-S equations for disturbances. The obtained stability equationsare solved by the Chebyshev spectral collocation method combined with the QZ algorithm to givethe complex dispersion relation w = w(a), where a is complex axial wave number and w is complexfrequency. The absolute growth rate w_0,i is the imaginary part of w at the point with vanishinggroup velocity dw/dk = 0. Various stability characteristics of the flow along with the variationof Mach number M, azimuthal wave number n, axial free velocity w_0 and swirling ratio q areobtained. Like incompressible case, the axial velocity strongly influence the absolute/convectiveinstability of supersonic trailing-line vortex. The absolute growth rate is largest when there isa reverse flow (W_0 = 0.8), and reduces more quickly than incompressible case as axial velocitydeficit decreases (w_0 increases). The flow is less unstable and changes from absolute unstable toconvectively unstable or even stable as Mach number increases. Also, the absolute growth ratereduces as azimuthal wave number increases from n = l, and this tendency is more appreciable athigher Mach numbers. The boundary between absolutely unstable region and convectively unstableregion on the M-q plane is given. It shows that the swirl can significantly enhance the absolutegrowth rate only in certain range of swirling ratio q = 0.2 ~ 0.5. All these results are significantto the investigation of enhancement of supersonic mixing.
%K absolute/convective instability
%K compressible trailing-line vortex
%K swirling flow
%K su-personic mixing
%K Chebyshev spectral collocation method<br>不稳定性
%K 可压缩
%K 尾涡
%K 旋拧流
%K 超声速混合
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=6E709DC38FA1D09A4B578DD0906875B5B44D4D294832BB8E&cid=5D344E2AD54D14F8&jid=4100DA4A1A3BA1B0CE5AD99AE1DFB420&aid=FA0FCCF43A9F0F078ED0C0B13FF19A3F&yid=B914830F5B1D1078&vid=4AD960B5AD2D111A&iid=B31275AF3241DB2D&sid=D02611D1F8166C9A&eid=C230D48775108CE3&journal_id=0459-1879&journal_name=力学学报&referenced_num=0&reference_num=5