China Aerodynamics Research and Development Center was founded in 1968. It is the largest research and testing institute of aerodynamics in China. The center is located in Mianyang City, Sichuan Province. Currently there are more than 1,600 scientists and technicians working there. Wikipedia.
Gao J.,Beihang University |
Gao J.,China Aerodynamics Research And Development Center
Journal of Computational Physics | Year: 2013
Overlap grid is usually used in numerical simulation of flow with complex geometry by high order finite difference scheme. It is difficult to generate overlap grid and the connectivity information between adjacent blocks, especially when interpolation is required for non-coincident overlap grids. In this study, an interface flux reconstruction (IFR) method is proposed for numerical simulation using high order finite difference scheme with multi-block structured grids. In this method the neighboring blocks share a common face, and the fluxes on each block are matched to set the boundary conditions for each interior block. Therefore this method has the promise of allowing discontinuous grids on either side of an interior block interface. The proposed method is proven to be stable for 7-point central DRP scheme coupled with 4-point and 5-point boundary closure schemes, as well as the 4th order compact scheme coupled with 3rd order boundary closure scheme. Four problems are numerically solved with the developed code to validate the interface flux reconstruction method in this study. The IFR method coupled with the 4th order DRP scheme or compact scheme is validated to be 4th order accuracy with one and two dimensional waves propagation problems. Two dimensional pulse propagation in mean flow is computed with wavy mesh to demonstrate the ability of the proposed method for non-uniform grid. To demonstrate the ability of the proposed method for complex geometry, sound scattering by two cylinders is simulated and the numerical results are compared with the analytical data. It is shown that the numerical results agree well with the analytical data. Finally the IFR method is applied to simulate viscous flow pass a cylinder at Reynolds number 150 to show its capability for viscous problem. The computed pressure coefficient on the cylinder surface, the frequency of vortex shedding, the lift and drag coefficients are presented. The numerical results are compared with the data of other researchers, and a good agreement is obtained. The validations imply that the proposed IFR method is accurate and effective for inviscid and viscous problems with complex geometry. © 2013 Elsevier Inc.
Yin F.,National University of Defense Technology |
Song J.,National University of Defense Technology |
Lu F.,China Aerodynamics Research And Development Center
Mathematical Methods in the Applied Sciences | Year: 2014
Klein-Gordon equation models many phenomena in both physics and applied mathematics. In this paper, a coupled method of Laplace transform and Legendre wavelets, named (LLWM), is presented for the approximate solutions of nonlinear Klein-Gordon equations. By employing Laplace operator and Legendre wavelets operational matrices, the Klein-Gordon equation is converted into an algebraic system. Hence, the unknown Legendre wavelets coefficients are calculated in the form of series whose components are computed by applying a recursive relation. Block pulse functions are used to calculate the Legendre wavelets coefficient vectors of nonlinear terms. The convergence analysis of the LLWM is discussed. The results show that LLWM is very effective and easy to implement. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.
Song Y.,Xian Jiaotong University |
Wang J.,Xian Jiaotong University |
Dai Y.,Xian Jiaotong University |
Zhou E.,China Aerodynamics Research And Development Center
Applied Energy | Year: 2012
This paper proposes a transcritical CO2 power cycle driven by solar energy while utilizing the cold heat rejection to an liquified natural gas (LNG) evaporation system. In order to ensure a continuous and stable operation for the system, a thermal storage system is introduced to store the collected solar energy and to provide stable power output when solar radiation is insufficient. A mathematical model is developed to simulate the solar-driven transcritical CO2 power cycle under steady-state conditions, and a modified system efficiency is defined to better evaluate the cycle performance over a period of time. The thermodynamic analysis focuses on the effects of some key parameters, including the turbine inlet pressure, the turbine inlet temperature and the condensation temperature, on the system performance. Results indicate that the net power output mainly depends on the solar radiation over a day, yet the system is still capable of generating electricity long after sunset by virtue of the thermal storage tank. An optimum turbine inlet pressure exists under given conditions where the net power output and the system efficiency both reach maximum values. The net power output and the system efficiency are less sensitive to the change in the turbine inlet temperature, but the condensation temperature exerts a significant influence on the system performance. The surface area of heat exchangers increases with the rise in the turbine inlet temperature, while changes in the turbine inlet pressure have no significant impact on the heat exchanging area under the given conditions. © 2011 Elsevier Ltd.
Le J.-L.,China Aerodynamics Research And Development Center
Tuijin Jishu/Journal of Propulsion Technology | Year: 2010
A status summary of our main progresses in the field of air-breathing hypersonic technology is present in this paper, including ground testing facility, scramjet, CFD methods and airframe/propulsion integrated vehicle. During past several years, three types of ground testing facility have been build and renovated in CARDC, which are pulse combustion facility, long duration combustion facility and arc-heated directly connected facility. Experiments of different size scramjet model have been carried out in our directly connected facilities and free-jet facilities. Performance, effects of fuel/air ratio, fuel injection and so on can be determined. Comparison of result between pulse facility and long duration facility indicates that the type of pulse facility with run duration more than 100 ms is an efficient way to test engine performance without cooling system. In the past ten years, a massively parallel CFD code named AHL3D is developed and widely used in many scramjet applications. Based on our several years' effort for technology readiness of hypersonic propulsion, a small scale airframe/propulsion integrated vehicle with 1.5m length was tested in our 0.6 m facility, engine performance and vehicle drag/thrust characteristics under engine powered and un-powered conditions was evaluated.
Hu H.,China Aerodynamics Research And Development Center |
Huang J.,China Aerodynamics Research And Development Center
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2015
Nonperturbative calculation of QED processes involving a strong electromagnetic field, especially provided by strong laser facilities at present and in the near future, generally resorts to the Furry picture with the use of analytical solutions of particle dynamical equations, such as the Klein-Gordon equation and Dirac equation. However, only for limited field configurations such as a plane-wave field could the equations be solved analytically. Studies have shown significant interest in QED processes in a strong field composed of two counterpropagating laser waves, but the exact solution in such a field is out of reach. In this paper, inspired by the observation of the structure of the solutions in a plane-wave field, we develop a method and obtain the analytical solution for the Klein-Gordon equation and equivalently the action function of the solution for the Dirac equation in this field, under a largest dynamical parameter condition that there exists an inertial frame in which the particle free momentum is far larger than the other field dynamical parameters. The applicable range of the solution is demonstrated and its validity is proven clearly. The result has the advantages of Lorentz covariance, clear structure, and close similarity to the solution in a plane-wave field, and thus favors convenient application. © 2015 American Physical Society.