scholarly journals A conceptual design for deflection device in VTDP system

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Yongwei Gao ◽  
Jianming Zhang ◽  
Long Wang ◽  
Bingzhen Chen ◽  
Binbin Wei
Keyword(s):  
Numerical Simulation ◽  
Power Consumption ◽  
Numerical Simulations ◽  
Conceptual Design ◽  
Lateral Force ◽  
Simulation Approach ◽  
Lower Power ◽  
Ducted Propeller ◽  
Vectored Thrust ◽  
Hovering Control

AbstractThe effectiveness of the Vectored Thrust Ducted Propeller (VTDP) system is not high currently, especially the lateral force is not large enough. Thus, a conceptual design for a deflection device of a VTDP system was proposed to achieve effective hovering control. The magnitude of the lateral force that was applied to maintain balance while hovering was examined. A comparison between the experimental and numerical results for the 16H-1 was made to verify the numerical simulation approach. The deflection devices of the X-49 and the proposed design were analyzed using numerical simulations. The results indicated that a larger lateral force and lower power consumption were presented in the proposed design. The results of this article provide a new idea for the design of the VTDP system.

scholarly journals A Conceptual Design for Deflection Device in VTDP System

2020 ◽  
Author(s):  
Yongwei Gao ◽  
Jianming Zhang ◽  
Long Wang ◽  
Bingzhen Chen ◽  
Binbin Wei
Keyword(s):  
Numerical Simulation ◽  
Power Consumption ◽  
Numerical Simulations ◽  
Conceptual Design ◽  
Lateral Force ◽  
Simulation Approach ◽  
Lower Power ◽  
Ducted Propeller ◽  
Vectored Thrust ◽  
Hovering Control

Abstract The effectiveness of the Vectored Thrust Ducted Propeller (VTDP) system is not high currently, especially the lateral force is not large enough. Thus, a conceptual design for a deflection device of a VTDP system was proposed to achieve effective hovering control. The magnitude of the lateral force that was applied to maintain balance while hovering was examined. A comparison between the experimental and numerical results for the 16H-1 was made to verify the numerical simulation approach. The deflection devices of the X-49 and the proposed design were analyzed using numerical simulations. The results indicated that a larger lateral force and lower power consumption were presented in the proposed design. The results of this article provide a new idea for the design of the VTDP system.

scholarly journals A Conceptual Design for Deflection Device in VTDP System

2020 ◽  
Author(s):  
Yongwei Gao ◽  
Jianming Zhang ◽  
Long Wang ◽  
Bingzhen Chen ◽  
Binbin Wei
Keyword(s):  
Numerical Simulation ◽  
Power Consumption ◽  
Numerical Simulations ◽  
Conceptual Design ◽  
Lateral Force ◽  
Simulation Approach ◽  
Lower Power ◽  
Ducted Propeller ◽  
Vectored Thrust ◽  
Hovering Control

Abstract A conceptual design for a deflection device of a Vectored Thrust Ducted Propeller (VTDP) system was proposed to achieve effective hovering control. The magnitude of the lateral force that was applied to maintain balance while hovering was examined. A comparison between the experimental and numerical results for the 16H-1 was made to verify the numerical simulation approach. The deflection devices of the X-49 and the proposed design were analyzed using numerical simulations. The results indicated that the proposed design provided a larger lateral force and lower power consumption.

scholarly journals Numerical Simulation of the Ducted Propeller and Application to a Semi-Submerged Vehicle

2020 ◽  
Vol 27 (2) ◽  
pp. 19-29
Author(s):  
Jin Zou ◽  
Guoge Tan ◽  
Hanbing Sun ◽  
Jie Xu ◽  
Yongkang Hou
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Open Water ◽  
The Self ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Ducted Propeller ◽  
Numerical Software ◽  
Numerical Approaches

AbstractThe self-propulsion test of underwater vehicles is the key technique for predicting and evaluating the navigation performance of these submersibles. In this study, the numerical simulation of a standard propeller JD7704+Ka4-70 is first presented and the results are compared with experiments to validate the numerical approaches. The reason why the propulsion efficiency of the ducted propeller is higher than that of the conventional propeller is explored. Then, the paper proposes a series of numerical simulations conducted to test the performance of the ducted propeller designed according to the JD7704+Ka4-70 in order to match with the unmanned semi-submerged vehicle (USSV), and the propeller’s open water characteristic curves are obtained. The results show a reasonable agreement with the regression analysis. Afterwards, the numerical simulations focus on a self-propulsion test of the USSV with the designed ducted propeller and the self-propulsion point is obtained. The streamlines through the hull as well as the ducted propellers are clearly obtained, together with the velocity distributions of the propeller plane. The results vividly demonstrate the hydrodynamic performance of the USSV with the designed propellers. In this paper, all the CFD simulations are based on the numerical software, Star-CCM+, and use the Reynolds-averaged Navier‒Stokes (RANS) equations with the shear stress transport (SST) k-omega turbulence model.

Numerical Investigation of Flow Structure in Pipe Elbow With Large Eddy Simulation Approach

2009 ◽  
Author(s):  
Masa-aki Tanaka ◽  
Hiroyuki Ohshima ◽  
Hideaki Monji
Keyword(s):  
Numerical Simulation ◽  
Large Eddy Simulation ◽  
Numerical Simulations ◽  
Flow Structure ◽  
Flow Condition ◽  
Simulation Approach ◽  
Simulation Code ◽  
Eddy Simulation ◽  
Pipe Elbow ◽  
Large Eddy

At the JAEA (Japan Atomic Energy Agency), the simulation code “MUGTHES (MUlti Geometry simulation code for THErmal-hydraulic and Structure heat conduction analysis in boundary fitted coordinate)” has been developed. MUGTHES employs LES (Large Eddy Simulation) approach to calculate unsteady thermal-hydraulic phenomena and the BFC (Boundary Fitted Coordinate) system to simulate complex geometry in the system. In this study, numerical simulations for pipe elbow flows in various curvature radius ratio (Rc/D) conditions at several Reynolds number conditions. By the numerical simulation in pipe elbow at a laminar flow condition of Re = 700, the numerical schemes and the evaluation method of metrics in BFC system are verified and an appropriate mesh arrangement for elbow pipe is considered. By the numerical simulations in pipe elbow with the ratio of Rc/D = 2 under turbulent flow condition of Re = 60,000, the LES approach using standard Smagorinsky model with wall function law is examined in comparison with the experimental results. Moreover, numerical simulation for the 1/3-scaled water experiment at Re = 3.7×106 which simulates the primary cooling system of the JSFR (Japan Sodium-cooled Fast Reactor) is conducted. From comparisons of axial velocity profiles, applicability of MUGTHES to the elbow pipe flow is confirmed and the characteristic of three-dimensional flow structure relating to the structural integrity of the elbow pipe is discussed.

scholarly journals Wind shear over the Nice Côte d'Azur airport: case studies

2013 ◽  
Vol 13 (9) ◽  
pp. 2223-2238 ◽  
Author(s):  
A. Boilley ◽  
J.-F. Mahfouf
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Numerical Simulations ◽  
Wind Shear ◽  
Horizontal Wind ◽  
Wind Profiler ◽  
Measurement Campaign ◽  
Wind Lidar ◽  
Real Time Applications ◽  
Wind Shears

Abstract. The Nice Côte d'Azur international airport is subject to horizontal low-level wind shears. Detecting and predicting these hazards is a major concern for aircraft security. A measurement campaign took place over the Nice airport in 2009 including 4 anemometers, 1 wind lidar and 1 wind profiler. Two wind shear events were observed during this measurement campaign. Numerical simulations were carried out with Meso-NH in a configuration compatible with near-real time applications to determine the ability of the numerical model to predict these events and to study the meteorological situations generating an horizontal wind shear. A comparison between numerical simulation and the observation dataset is conducted in this paper.

Stefan Number-Insensitive Numerical Simulation of the Enthalpy Method for Stefan Problems Using the Space-Time Conservation Element and Solution Element Method

2004 ◽  
Author(s):  
Anahita Ayasoufi ◽  
Theo G. Keith ◽  
Ramin K. Rahmani
Keyword(s):  
Numerical Simulation ◽  
Phase Change ◽  
Numerical Simulations ◽  
Latent Heat ◽  
Space Time ◽  
Enthalpy Method ◽  
Stefan Problems ◽  
Stefan Number ◽  
Original Scheme ◽  
Solution Element

An improvement is introduced to the conservation element and solution element (CE/SE) phase change scheme presented previously. The improvement addresses a well known weakness in numerical simulations of the enthalpy method when the Stefan number, (the ratio of sensible to latent heat) is small (less than 0.1). Behavior of the improved scheme, at the limit of small Stefan numbers, is studied and compared with that of the original scheme. It is shown that high dissipative errors, associated with small Stefan numbers, do not occur using the new scheme.

A LOW-POWER AND HIGH-SPEED D FLIP-FLOP USING A SINGLE LATCH

2002 ◽  
Vol 11 (01) ◽  
pp. 51-55
Author(s):  
ROBERT C. CHANG ◽  
L.-C. HSU ◽  
M.-C. SUN
Keyword(s):  
Power Consumption ◽  
Low Power ◽  
Power Dissipation ◽  
High Speed ◽  
Operating Frequency ◽  
Flip Flop ◽  
Lower Power ◽  
Simulation Results ◽  
Hspice Simulation

A novel low-power and high-speed D flip-flop is presented in this letter. The flip-flop consists of a single low-power latch, which is controlled by a positive narrow pulse. Hence, fewer transistors are used and lower power consumption is achieved. HSPICE simulation results show that power dissipation of the proposed D flip-flop has been reduced up to 76%. The operating frequency of the flip-flop is also greatly increased.

Pneumatic pulsator design as an example of numerical simulations in engineering applications

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Krzysztof Wołosz ◽  
Jacek Wernik
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Cast Iron ◽  
Numerical Simulations ◽  
Stress Analysis ◽  
Aluminium Alloy ◽  
Loose Material ◽  
Engineering Applications ◽  
Pressure Losses ◽  
Pneumatic Impact

AbstractThe paper presents the part of the investigation that has been carried out in order to develop the pneumatic pulsator which is to be employed as an unblocking device at lose material silo outlets. The part of numerical simulation is reported. The fluid dynamics issues have been outlined which are present during supersonic airflow thought the head of the pulsator. These issues describe the pneumatic impact phenomenon onto the loose material bed present in the silo to which walls the pulsator is assembled. The investigation presented in the paper are industrial applicable and the result is the working prototype of the industrial pneumatic pulsator. The numerical simulation has led to change the piston shape which is moving inside the head of the pulsator, and therefore, to reduce the pressure losses during the airflow. A stress analysis of the pulsator controller body has been carried out while the numerical simulation investigation part of the whole project. The analysis has made possible the change of the controller body material from cast iron to aluminium alloy.

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