scholarly journals A feature-based mesh adaptation for the unsteady high speed compressible flows in complex three-dimensional domains

2016 ◽  
Vol 40 (3) ◽  
pp. 1728-1740
Author(s):  
Hoang-Huy Nguyen ◽  
Vinh-Tan Nguyen ◽  
Matthew A. Price ◽  
Oubay Hassan
Author(s):  
Y Wang ◽  
S Komori

A pressure-based finite volume procedure developed previously for incompressible flows is extended to predict the three-dimensional compressible flow within a centrifugal impeller. In this procedure, the general curvilinear coordinate system is used and the collocated grid arrangement is adopted. Mass-averaging is used to close the instantaneous Navier-Stokes equations. The covariant velocity components are used as the main variables for the momentum equations, making the pressure-velocity coupling easier. The procedure is successfully applied to predict various compressible flows from subsonic to supersonic. With the aid of the k-ɛ turbulence model, the flow details within a centrifugal impeller are obtained using the present procedure. Predicted distributions of the meridional velocity and the static pressure are reasonable. Calculated radial velocities and flow angles are favourably compared with the measurements at the exit of the impeller.


2016 ◽  
Vol 846 ◽  
pp. 67-72
Author(s):  
Samuel Stennett ◽  
Wilson Chan ◽  
David E. Gildfind ◽  
Peter Jacobs

The computational fluid dynamics solver Eilmer has proven useful to The University of Queensland’s Centre for Hypersonics for its ability to simulate high-speed compressible flows. In Eilmer, turbulence is modelled using Wilcox’s 2006 k-ω model. While the turbulence model implementation has been validated for two-dimensional and axisymmetric flows, validation is required for three-dimensional flows. The present paper describes the progress of the validation of the k-ω turbulence model for two three-dimensional test cases. A case featuring Mach 4.5 air flow over a flat plate produced results that correlated with previous numerical results within 4%. A second case featuring the injection of Mach 1 air into a Mach 4 air cross-flow produced results indicating that the code successfully captured the main flow features.


2003 ◽  
Vol 17 (10) ◽  
pp. 1041-1056
Author(s):  
Yoshihiro Nakabo ◽  
Idaku Ishii ◽  
Masatoshi Ishikawa

2011 ◽  
Vol 243-249 ◽  
pp. 3670-3675
Author(s):  
Yun Dong Ma ◽  
Bo Li ◽  
Bin Fan

The aerodynamic numerical simulation model of high-speed railway tunnel was established based on the analyzing of the aerodynamic effect characteristics of high-speed railway tunnel. FLUENT three dimensional compressible flows SIMPLE algorithm was adopted, the three dimensional aerodynamic effect of high-speed railway tunnel was simulated on the condition that the high-speed train was in motion. The pressure changes law in the tunnel was obtained during the whole process when high-speed train traveling, and the pressure-time curve in the tunnel middle cross-section was plotted. It laid a foundation for the further development of tunnel lining dynamics analysis.


Author(s):  
Robert W. Mackin

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.


2021 ◽  
Author(s):  
Scott J. Peltier ◽  
Brian E. Rice ◽  
Ethan Johnson ◽  
Venkateswaran Narayanaswamy ◽  
Marvin E. Sellers

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