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951.
定态火焰在可燃预混气中产生的压力波 总被引:1,自引:0,他引:1
火焰在可燃预混气中传播时,在火焰面前方产生一道压力波。忽略点火及火焰的初期加速,仅考虑火焰达到稳定传播速度的情况。用Openheim自相似解分析流场,得到相应的控制方程及定解条体;用自适应步长的四阶Runge-Kutta法对方程积分,讨论了流场压力波结构及弱激波近似声波解;认为火焰为间断面,能量释放在火焰面后瞬时完成。利用火焰面两侧的能量关系,得到了火焰位置、燃速及对应C-J条件的火焰位置、C-J燃速。 相似文献
952.
数值研究激波与旋涡的相互作用 总被引:4,自引:1,他引:4
从非定常形式的Euler方程出发,数值模拟了运动激波与旋涡相互作用的非定常流动过程。为保证激波具有较高的分辨率,采用对称型TVD格式进行了数值计算。结果表明。这样可以有效地模拟流场中一些复杂的流动现象,如激波变形、激波分叉和三波点的形成,以及旋涡结构的变化过程等,并与已有的实验流动显示相符良好。同时,也是对TVD格式求解这类问题的一次初步尝试。 相似文献
953.
A finite difference method is developed for the numerical modelling of the 2-D and 3-D unsteady potential flow generated by
transient disturbances on the free surface, on which the nonlinear boundary conditions are fully satisfied. The unknown function
is computed with an iteration scheme processing in a transformed time-invariant space. After the velocity is calculated, the
location of the free surface is renewed and so is the value of velocity on it. The boundary-value problem of the governing
equation is then solved at the next time step. The present method incorporates the FFT. Consequently, a tri-diagonal equation
system is obtained which could be readily solved. The feasibility of this method has been demonstrated by 2-D and 3-D examples
corresponding to different initial disturbances.
This work is supported by the science foundation of Academia Sinica.
The paper had been accepted by the XVIth International Congress of IUTAM, Lyngby, Denmark, August, 1984. 相似文献
954.
The reflection and diffraction of a planar shock wave around a circular cylinder are a typical problem of the complex nonlinear
shock wave phenomena in literature. It has long been studied experimentally, analytically as well as numerically. Takayama
in 1987 obtained clear experimental pictures of isopycnics in shock tube under the condition that the impinging shock wave
propagates as far as 3 diameters away from the cylinder. To know more completely the whole unsteady process, it is desirable
to get experimental results in a region which is more than 10 diameters away from the cylinder. This is what has been done
in this paper by using the pulsed laser holographic interferometry for several shock Mach numbers of the impinging shock.
Results for several moments are shown, giving more knowledge about the whole unsteady flow field. This is useful for a reliable
and complete understanding of the changing force acting on the cylinder, and provides interesting data to check the performance
of many recently developed high resolution numerical methods for unsteady shock wave calculation.
The project suported partially by National Natural Science Foundation of China 相似文献
955.
956.
Acoustic waves scattering from a rigid air-saturated porous medium is studied in the time domain. The medium is one dimensional and its physical parameters are depth dependent, i.e., the medium is layered. The loss and dispersion properties of the medium are due to the fluid-structure interaction induced by wave propagation. They are modeled by generalized susceptibility functions which express the memory effects in the propagation process. The wave equation is then a fractional telegraphists equation. The two relevant quantities are the scattering operators—transmission and reflection operators—which give the scattered fields from the incident wave. They are obtained from Volterra equations which are fractional equations for the scattering operators. 相似文献
957.
FengWenjie WangLiqun JiangZhiqing ZhaoYongmao 《Acta Mechanica Solida Sinica》2004,17(3):258-269
I. INTRODUCTION Owing to the intrinsic coupling characteristics between electric and elastic behaviors, piezoelectricmaterials have been used widely in technology such as transducers, actuators, sensors, etc. Studieson electroelastic problems of a piezo… 相似文献
958.
959.
A new nonlinear wave equation of a finite deformation elastic circular rod simultaneously introducing transverse inertia and shearing strain was derived by means of Hamilton principle. The nonlinear equation includes two nonlinear terms caused by finite deformation and double geometric dispersion effects caused by transverse inertia and transverse shearing strain. Nonlinear wave equation and corresponding truncated nonlinear wave equation were solved by the hyperbolic secant function finite expansion method. The solitary wave solutions of these nonlinear equations were obtained. The necessary condition of these solutions existence was given also. 相似文献
960.
有限长Timoshenko梁弹性碰撞接触瞬间的动态特性 总被引:5,自引:1,他引:5
给出了质点与有限长Timoshenko梁横向弹性碰撞接触问题的半解析解,分析了该碰撞问题在碰撞接触瞬间的动态响应特性:揭示了其中的波传播现象. 相似文献