New Three-Dimensional Inverse Method for High-Speed Vehicle Design

The development and application of a three-dimensional inverse methodology in which the blade geometry is computed on the basis of the specification of static pressure loading distribution is presented. The methodology is based on the intensive use of computational fluid dynamics (CFD) to account for three-dimensional subsonic and transonic viscous flows. In the design computation, the necessary blade changes are determined directly by the discrepancies between the target and initial values, and the calculation converges to give the final blade geometry and the corresponding steady state flow solution. The application of the method is explored using a transonic test case, NASA rotor 67. Based on observations, it is conclusive that the shock formation and its intensity in such a high-speed turbomachinery flow are well defined on the loading distributions. Pressure loading is therefore as effective a design parameter as conventional inverse design quantities such as static pressure. Hence, from an understanding of the dynamics of the flow in the fan in relation to its pressure loading distributions, simple guidelines can be developed for the inverse method in order to weaken the shock formation. A qualitative improvement in performance is achieved in the redesigned fan. The final flowfield result is confirmed by a well-established commercial CFD package.

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A conceptual design tool to support high-speed vehicle design

AIAA AVIATION 2020 FORUM ◽

10.2514/6.2020-2647 ◽

2020 ◽

Author(s):

Davide Ferretto ◽

Roberta Fusaro ◽

Nicole Viola

Keyword(s):

Conceptual Design ◽

High Speed ◽

Design Tool ◽

Vehicle Design ◽

High Speed Vehicle

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Study on afterbody-effects of multi-stage separation at high-speed

Journal of Physics Conference Series ◽

10.1088/1742-6596/2083/3/032076 ◽

2021 ◽

Vol 2083 (3) ◽

pp. 032076

Author(s):

Yongqian Zheng ◽

Hongyin Jia ◽

Pengcheng Cui ◽

Huan Li ◽

Xiaojun Wu

Keyword(s):

Drag Coefficient ◽

High Speed ◽

Dynamic Pressure ◽

Three Dimensional ◽

Strong Shock ◽

Aerodynamic Characteristics ◽

Second Stage ◽

Stage Separation ◽

Multi Stage ◽

High Speed Vehicle

Abstract The stage separation of high-speed vehicle is complicated at high dynamic pressure, usually accompanied by strong shock and vortex interaction. There exists a strong interaction between first stage and second stage, which called “afterbody-effects”. The aerodynamic mechanism of “afterbody-effects” is studied in this paper based on numerical simulation. The aerodynamic characteristics of a simplified three-dimensional projectile model at different distances between stages at 0° angle of attack is researched with structural mesh. The results show that the vortexes of stages have a significant impact on the aerodynamic characteristics of different stages, As the distance between stages increases, the drag coefficient of the first stage increases, and the drag coefficient of the second stage increases first and then decreases.

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High-speed brightfield 3-D imaging and 3-D image analysis of thick and overlapped cell clusters in cytological preparations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100168827 ◽

1994 ◽

Vol 52 ◽

pp. 218-219

Author(s):

Robert W. Mackin

Keyword(s):

Image Analysis ◽

High Speed ◽

Three Dimensional ◽

Image Data ◽

Ccd Camera ◽

Objective Lens ◽

Array Processor ◽

Vaginal Smears ◽

Low Contrast ◽

Computer Controlled

This paper presents two advances towards the automated three-dimensional (3-D) analysis of thick and heavily-overlapped regions in cytological preparations such as cervical/vaginal smears. First, a high speed 3-D brightfield microscope has been developed, allowing the acquisition of image data at speeds approaching 30 optical slices per second. Second, algorithms have been developed to detect and segment nuclei in spite of the extremely high image variability and low contrast typical of such regions. The analysis of such regions is inherently a 3-D problem that cannot be solved reliably with conventional 2-D imaging and image analysis methods.High-Speed 3-D imaging of the specimen is accomplished by moving the specimen axially relative to the objective lens of a standard microscope (Zeiss) at a speed of 30 steps per second, where the stepsize is adjustable from 0.2 - 5μm. The specimen is mounted on a computer-controlled, piezoelectric microstage (Burleigh PZS-100, 68/μm displacement). At each step, an optical slice is acquired using a CCD camera (SONY XC-11/71 IP, Dalsa CA-D1-0256, and CA-D2-0512 have been used) connected to a 4-node array processor system based on the Intel i860 chip.

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