Abstract
This article studies the nonlinear evolution of disturbance waves in supersonic nonparallel boundary layer flows by using
nonlinear parabolic stability equations (NPSE). An accurate numerical method is developed to solve the equations and march the
NPSE in a stable manner. Through computation, are obtained the curves of amplitude and disturbance shape function of harmonic waves. Especially are demonstrated the physical characteristics of nonlinear stability of various harmonic waves, including instantaneous stream wise vortices, spanwise vortices and Λ structure etc, and are used to study and analyze the mechanism
of the transition process. The calculated results have evidenced the effectiveness of the proposed NPSE method to research the
nonlinear stability of the supersonic boundary layers.
Keywords: boundary layer stability; nonlinearity; supersonic flow; nonparallelism; nonlinear parabolic stability equations
ترجمه ماشینی
چکیده
در این مقاله تکامل غیر خطی امواج اختلال در جریان لایه مرزی nonparallel مافوق صوت با استفاده از
معادلات غیر خطی سهموی ثبات (NPSE). یک روش دقیق عددی برای حل معادلات و مارس
بینی به شیوه ای پایدار است. از طریق محاسبه هستند، منحنی تابع شکل دامنه و اختلال در امواج هارمونیک دست آمده است. به خصوص نشان داد ویژگی های فیزیکی ثبات غیرخطی امواج مختلف هارمونیک، از جمله آنی جریان گردابه دانا، گرداب جهت span و ساختار Λ و غیره، و برای مطالعه و تجزیه و تحلیل مکانیزم استفاده می شود
از روند گذار. نتایج محاسبه اثربخشی روش NPSE پیشنهاد مشهود به تحقیق
ثبات غیر خطی از لایه های مرزی مافوق صوت است.
کلمات کلیدی: ثبات لایه مرزی؛ غیرخطی؛ جریان مافوق صوت؛ غیر موازی؛ معادلات سهموی ثبات غیر خطی
Closely related to the determination of the transition
location and the control of boundary layers, the stability and transition of boundary layer flows are of critical importance during designing the aerial vehicles.
With the dramatic development of the aeronautics and
astronautics over recent years, more and more attention has been paid to the stability and the transition of
supersonic boundary layer flows. Researches on stability, especially, on nonlinear stability proved very difficult to pursue because of the violent variation of
many influencing parameters and acute interactions in
supersonic boundary layer flows[1].
The stability theory has long been adopted to study
disturbance evolution in boundary layers. As the linear
parallel stability theory commonly ignores the nonparallel and the nonlinear effects[2-3], the obtained results
are generally somewhat different from the reality. As a
result, many methods, which consider either of the two
effects, are put forward. Till now, the direct numerical
simulation (DNS) of Navier-Stokes equations[4-5]
seems the most powerful technique to deal with the
stability phenomena, for it can simulate the whole
Nonlinear Stability of Supersonic Nonparallel Boundary Layer Flows (مقاله لاتین می باشد و فاقد ترجمه می باشد7ص )