High-Speed Magnetohydrodynamic Flow Control Analyses with Three-Dimensional Simulations

2008 ◽  
Vol 24 (5) ◽  
pp. 946-961 ◽  
Author(s):  
Datta V. Gaitonde
Keyword(s):  
Flow Control ◽  
High Speed ◽  
Three Dimensional ◽  
Magnetohydrodynamic Flow ◽  
Three Dimensional Simulations

Exploratory Studies on the Control of High-Speed Flows With Magnetogasdynamics

2002 ◽  
Author(s):  
Datta V. Gaitonde
Keyword(s):  
Flow Control ◽  
High Speed ◽  
Three Dimensional ◽  
Experimental Investigations ◽  
Control Mechanisms ◽  
Ground Testing ◽  
Simulation Efficiency ◽  
The Status ◽  
Physical Phenomena ◽  
Insight Into

Magnetogasdynamics (MGD) has the potential to lift many of the constraints presently inhibiting sustained hypersonic flight and affordable access to space. Given the difficulty of ground-testing under the expected harsh conditions, numerical methods can provide insight into the physical phenomena, and thus complement experimental investigations in the development of future concepts. This paper describes the status of an effort to develop a high-fidelity, fully three-dimensional method to explore MGD flow control in complex configurations. The theoretical model includes several non-ideal effects and takes recourse to a blend of first principles and phenomenological approaches to enhance simulation efficiency. Boundary conditions are summarized and sample verification exercises are presented. Exploratory calculations on a reentry vehicle and flow-through scramjet flowpath with MGD-bypass demonstrate the versatility of the approach and yield insight into dominant flow control mechanisms.

Numerical Investigation of Three-dimensional Separation Control on a High-speed Compressor Stator Vane with Tailored Synthetic Jet

2020 ◽  
Vol 37 (4) ◽  
pp. 383-397 ◽  
Author(s):  
Yong Qin ◽  
Yanping Song ◽  
Ruoyu Wang ◽  
Huaping Liu
Keyword(s):  
Flow Control ◽  
Flow Separation ◽  
High Speed ◽  
Numerical Study ◽  
Three Dimensional ◽  
Synthetic Jet ◽  
Separation Control ◽  
Flow Separation Control ◽  
Control Efficiency ◽  
Stator Vane

AbstractA numerical study on the performance of synthetic jet for flow separation control on a high-speed compressor stator vane is performed. Four control schemes including full-span and part-span configurations are investigated at both design and off-design conditions. Results indicate that both full-span and part-span schemes could effectively delay flow separation and reduce total pressure loss for the compressor stator vane, the adaptability of the flow control under off-design conditions is also validated. Within the investigated incidence range, the full-span configuration is able to gain the most significant performance improvement, by which a maximum loss reduction of 23.8 % is obtained at i=2 deg. The part-span configuration could reorganize the vortex structures more efficiently and cut off the interaction between the ring-like vortex and the passage vortex, thus improving its performance in the corner region. In terms of flow control efficiency, the part-span configurations turn out to be more superior, where the highest control efficiency of 614.0 % is achieved at i=0 deg with the total height of the actuator being 40 %H. The flow control efficiency for all the schemes is higher than 100 % within the whole operating range, demonstrating a promising prospect for the application of synthetic jet in axial compressors.

Investigation of Turbulence Modeling in a High Speed Centrifugal Pump With an Inducer

2007 ◽  
Author(s):  
Behrooz Jafarzadeh ◽  
Reza Mokhtarpoor ◽  
Mohammad Mehdi Alishahi ◽  
Mohammad Hadi Akbari
Keyword(s):  
Centrifugal Pump ◽  
High Speed ◽  
Turbulence Modeling ◽  
Flow Direction ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Governing Equations ◽  
Flow Rates ◽  
Pressure Fields ◽  
Three Dimensional Simulations

In this paper, investigation of turbulence modeling for a centrifugal pump is presented in the form of characteristic curves. A commercial CFD code was used to solve the governing equations of the flow field. Turbulent flow is simulated by employing standard k-ε, RNG and RSM models. Existence of an inducer in the flow direction to prevent cavitation makes two-dimensional simulations of the present configuration impossible. Three-dimensional simulations were therefore performed to predict velocity and pressure fields at different flow rates. Considering the only one available experimental data, the optimum turbulence model for the problem was found. Additionally, effect of number of blades on the efficiency of pump was studied. The number of blades was changed from 6 to 5 and 7, then all calculations were performed afresh. Investigations of this kind may help reduce the required experimental work for the development and design of such devices.

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

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.

Effects of Three-Dimensional Pressure Gradients on High-Speed Turbulent Boundary Layers

2021 ◽  
Author(s):  
Scott J. Peltier ◽  
Brian E. Rice ◽  
Ethan Johnson ◽  
Venkateswaran Narayanaswamy ◽  
Marvin E. Sellers
Keyword(s):  
Boundary Layers ◽  
High Speed ◽  
Three Dimensional ◽  
Turbulent Boundary Layers ◽  
Pressure Gradients
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