An Evolution of Hybrid Airship Vehicle (HAV) Envelope: Aerodynamics Analysis

HAV has a potential application as the new means to carry Ultra Heavy Payload cargo since it combines the buoyancy capabilities of Lighter-than-Air (LTA), and the aerodynamics of lifting body of Heavier-than-Air (HTA) for speed. Due to its potential, American Institute of Aeronautics and Astronautics (AIAA) has issued a Request for Proposal (RFP) regarding the Hybrid Airship Vehicle (HAV) as cargo transportation with several requirements. AIAA RFP required an envelope that can produce 60% of the lift from buoyancy and 40% of lift from aerodynamic. To satisfy the RFP requirements, this paper analyzed 4 different designs using Computational Fluid Dynamic (CFD) software. Design 4 was chosen as the final design because it meets all the requirements. It was found that at 5° Angle of Attack (AOA), the envelope produce highest aerodynamic lift over drag (L/D) ratio of 3.79. At higher AOA, flow separation occurs at the envelope tail section jeopardizing the aerodynamic characteristic of Design 4 envelope. The lift and drag force graphs were plotted at this AOA and it was found that the HAV envelope is capable of performing the tasks in the RFP.

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Simulation of Aerosol Sampling Inlet for Different Outlet Angle

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.483.234 ◽

2013 ◽

Vol 483 ◽

pp. 234-237

Author(s):

Bao Qing Wang ◽

Ze Bei Wang ◽

Yang Yang Li ◽

Rong Hui Chen ◽

Shu Yao

Keyword(s):

Pressure Distribution ◽

Computational Fluid Dynamic ◽

High Efficiency ◽

Cfd Simulation ◽

Fluid Dynamic ◽

Aerosol Sampling ◽

Outlet Angle ◽

Final Design

Performance of aerosol sampling inlet for different diffuser outlet angle is compared with its velocity and pressure distribution. To get information on velocity and pressure distribution for different outlet angle, Computational Fluid Dynamic (CFD) simulation can be used. At the same time, it can achieve high efficiency of aerosol sampling and minimize disturbance to the aircraft which carries the system. The final design for the sampling inlet is determined to be a design with diffuser outlet angle of 15 degree. This design was selected to keep stable for velocity and pressure, and have a less length.

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Analysis of lift and drag coefficients of a GT2 racing car at various speeds with movable wheels and ground

World Journal of Engineering ◽

10.1260/1708-5284.12.3.261 ◽

2015 ◽

Vol 12 (3) ◽

pp. 261-270

Author(s):

Albert Boretti

Keyword(s):

Wind Tunnel ◽

Drag Force ◽

Computational Fluid Dynamic ◽

Lift Force ◽

Fluid Dynamic ◽

Time Simulation ◽

Rear Wing ◽

Speed Range ◽

Drag And Lift ◽

Lift And Drag

The paper proposes a study of a GT2 racing car with a computational fluid dynamic (CFD) tool. Results of STAR-CCM+ simulations of the flow around the car in a wind tunnel with movable ground and wheels are presented for different air speeds to assess the different contributions of pressure and shear to lift and drag over the speed range. The rear wing contributes more than 85% of the lift force and 7-8% of the drag force for this particular class of racing cars. When reference is made to the low speed drag and lift coefficients, increasing the speed from 25 to 100 m/s produces an increase of CD of more than 3% and a reduction of CL of more than 2%. The resultsuggests modifying the constant CD and CL values used in lap time simulation toolsintroducing the tabulated values to interpolate vs. the speed of the car.

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