CFD++介绍

CFD++/CAA++介绍
张杰博士
2009年9月24日
报告内容
¾气动分析软件CFD++/CAA++介绍¾CFD++/CAA++小结
CFD++的UNIFIED原则
CFD++的软硬件平台支持
CFD++的流动求解范围
CFD++的数值方法
CFD++的高效解决方法
CFD++的非定常处理
CFD++的湍流和转捩
CFD++的湍流模型
CFD++的物理模型
CFD++的重点应用领域
CFD++的精度
CFD++的可信度
CFD++的效率
Benchmark:DLR模型
Benchmark:阻力预测
Benchmark:阻力预测
典型应用:F18战斗机
典型应用:直升机
典型应用:飞机模拟
典型应用:大规模数值模拟
CFD++求解高速流动-轨道器
CFD++求解高速流动-X38
¾Mach 6.0 ,40.0 degree angle of attack;
¾turbulent flow single equation Rt
model, wall function;
¾heat transfer effects.
The pictures show vehicle:
¾wall pressure and temperature;
¾representative streamlines;
¾crossflow behavior.
CFD++求解高速流动-导弹
Aerodynamics of Non-Axisymmetric Missiles:
¾For the U.S Army Research Laboratory;
¾Matched well with experiment data;
CFD++求解高速流动-火箭分离
Stage Separation:
¾For the U.S Army Research Laboratory;
¾Show moving mesh ability of CFD++;
¾Matched well with experiment data.
CFD++求解高速流动-化学反应
¾Free Stream Mach number 5.9
¾Plume expands to Mach 12.0
¾15 Species, 18 Reactions ,Total of 21 equations
¾Captured the re-compression point successfully
¾Matched experimental data very well
CFD++求解高速流动-预混燃烧
实验纹影
甲烷
水
温度
CFD++求解高速流动-高超进气道
¾Mach number 8.3,250,000 cells
¾Y+~60,with wall function and heat transfer
¾One equation Rt model turbulent model
¾Matched experimental data very well
CAA++介绍
计算气动声学背景介绍
计算气动声学（CAA ）为气动力学和声学交叉的分支学科，着重研究流动及其物体作用导致噪声的机理。

声场脉动量比流动物理参数量级相差悬殊，对时间、空间离散格式要求较高，否则数值误差会掩盖噪声效应； 空间、时间尺度范围较宽，造成计算域较大，对计算机资源提出很高要求。

1992年，美国ICASE 和NASA 联合举办了讨论会，确立了（CAA ）的地位。

CAA 理论的发展以声学模拟理论的建立为标志，其主要特点有：
CAA++的技术创新
先进的气动声学求解工具NLAS。

气动声学预测不再受经验模型或LES的限制；
RANS/LES NLAS
CAA++ CFD++
CAA++
混合CAA++
CAA++特点
全频域分析；
先进的亚网格噪声源随机模型； 解析拓展未求解尺度和远场。

喷管流动噪声分析
NLAS simulation of the near-field transonic jet flow
¾a transonic cold air jet issuing from a converging nozzle section;
¾The initial statistics for the acoustics solver were computed using a cubic k-epsilon RANS model;
¾the acoustics data was subsequently interpolated on to an acoustics mesh with a reduced outer domain and relaxed near-wall stretching;
¾far-field boundary treatment allowed NLAS to operate on a mesh of approximately 500,000 cells, compared with 3.5 million for that of the initial steady-state RANS calculation.
Acoustics Simulation of the Flow-Induced Noise from a Transonic Jet:
三段翼型噪声计算结果
NLAS simulation of high-lift trap-wing configuration
¾low Mach number flow over a high-lift device;
¾The NLAS simulation is shown here in terms of the acoustic pressure radiated from the turbulent shear layers and, in particular, the separated flow in the slat cove.
Acoustics Simulation of the Flow-Induced Noise from a High-Lift Trap-Wing Configuration:
CFD++/CAA++小结
Thanks for your attention!。