PART 1 - LONGITUDINAL AND DRAG CHARACTERISTICS, WIND TUNNEL TESTS OF A 1/48 SCALE MODEL OF THE XZS2-G-1 AIRSHIP WITH VARIOUS TAIL CONFIGURATIONS

1954 ◽  
Author(s):  
ARNOLD W. ANDERSON ◽  
JR FLICKINGER ◽  
SAMUEL J.
Keyword(s):  
Wind Tunnel ◽  
Scale Model ◽  
Wind Tunnel Tests

Wind Loading on a Pyramidal Roof Structure

1985 ◽  
Vol 1 (2) ◽  
pp. 105-110 ◽  
Author(s):  
A. J. Dutt
Keyword(s):  
Wind Tunnel ◽  
Peripheral Region ◽  
Wind Pressure ◽  
Scale Model ◽  
Wind Loading ◽  
Wind Tunnel Experiments ◽  
Wind Tunnel Tests ◽  
Roof Structure ◽  
Inner Region ◽  
The Church

This paper deals with the investigation of wind loading on the pyramidal roof structure of the Church of St Michael in Newton, Wirral, Cheshire, England, by wind tunnel tests on a 1/48 scale model. The roof of the model was flat in the peripheral region of the building while in the inner region there was a grouping of four pyramidal roofs. Wind tunnel experiments were carried out; wind pressure distribution and contours of wind pressure on all surfaces of the pyramid roofs were determined for four principal wind directions. The average suctions on the roof were evaluated. The highest point suction encountered was — 4q whilst the maximum average suction on the roof was —0·86q. The results obtained from wind tunnel tests were used for the design of pyramidal roof structures and roof coverings for which localised high suctions were very significant.

scholarly journals Planetary Atmosphere Wind Tunnel Tests on Aerodynamic Characteristics of a Mars Airplane Scale Model

2014 ◽  
Vol 12 (ists29) ◽  
pp. Pk_7-Pk_12 ◽  
Author(s):  
Masayuki ANYOJI ◽  
Masato OKAMOTO ◽  
Hidenori HIDAKA ◽  
Taku NONOMURA ◽  
Akira OYAMA ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Planetary Atmosphere ◽  
Scale Model ◽  
Wind Tunnel Tests

Vortex Shedding From Struts in an Annular Exhaust Diffuser

1998 ◽  
Vol 120 (1) ◽  
pp. 186-192 ◽  
Author(s):  
T. F. Fric ◽  
R. Villarreal ◽  
R. O. Auer ◽  
M. L. James ◽  
D. Ozgur ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Gas Turbine ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Scale Model ◽  
Bluff Bodies ◽  
Cylinder Wake ◽  
Wind Tunnel Tests ◽  
Full Speed ◽  
Inlet Swirl

Results from scale-model experiments and industrial gas turbine tests show that strut vortex shedding in an annular exhaust diffuser can effectively be modified by adding tapered chord to the struts. The struts are bluff bodies at full-speed, no-load conditions, when inlet swirl is close to 60 deg. Data from wind tunnel tests show that wake Strouhal number is 0.47, larger than that expected for an isolated cylinder wake. This value of Strouhal number agrees with those measured in full-scale exhaust diffusers. Wind tunnel tests showed that a strut with tapered chord most effectively reduced wake amplitudes and shifted shedding frequency. The tapered strut was also effective in reducing shedding amplitude in a scale-model diffuser. Finally, gas turbine tests employing a tapered strut showed significant reductions in unsteady pressure and noise. A major benefit of strut taper is a reduction of noise by uncoupling of vortex shedding from acoustic resonant response.

Current Forces on Prelude Hull and Water Intake Riser by CFD: Full Scale Model Using Two of the World’s Largest Supercomputers

2021 ◽  
Author(s):  
Erwan Auburtin ◽  
Jang Kim ◽  
Hyunchul Jang ◽  
Lawrence Lai ◽  
Jason McConochie ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Water Intake ◽  
Full Scale ◽  
Scale Model ◽  
Accurate Estimation ◽  
Correct Prediction ◽  
Wind Tunnel Tests ◽  
Numerical Predictions

Abstract The Prelude Floating Liquefied Natural Gas (FLNG) facility is moored with an internal turret allowing it to perform offloading operations of liquefied natural and petroleum gas products. It does so in either a Free Weathervaning (FW) mode, i.e. by allowing the unit to rotate according to environmental loads, or in a Thruster-Assisted (TA) mode, i.e. by using the stern thrusters to maintain a fixed heading deemed preferable for the entire operation, or a particular phase. An accurate estimation of the various environment effects, in terms of forces on the FLNG and LNG carrier, is critical to ensure a correct prediction of its heading or the required thruster forces, depending on the selected operating mode. The predominant loads driving the weathervaning behavior are wind and current loads. These loads have been estimated from wind tunnel tests during the engineering phase. Since the Prelude FLNG has been installed on-site, field measurements have provided an opportunity for comparison and shown some differences with the numerical predictions based on the estimated loads, prompting a need for verification of current loads by an independent method. For the Prelude FLNG application, current loads play an important role due to facility size and significant tidal currents. It has been shown in some previous studies that wind tunnel tests for a model of under-water geometry may underestimate current loads compared to those on a full-scale vessel. There is a boundary layer along the wind tunnel floor in wind tunnel tests, while the current profile is relatively uniform over the hull draft in the real ocean condition. Moreover experimental tests present some additional drawbacks: they are performed at a reduced scale (1:225), the Reynolds number is lower than full-scale even with a large wind tunnel speed, and it is difficult to model the long (150m full-scale) Water Intake Risers (WIR) extending below the hull bottom. In order to investigate these effects, state-of-the-art full-scale CFD simulations were performed for the Prelude hull and WIR. The test program included different current speeds and directions, and several sensitivity studies: Reynolds number effect between model- and full-scales, effect of current speed profile (comparing uniform and boundary layer profiles at model scale), effect of FLNG rotation in yaw, impact of unsteady current, and presence of marine growth. Extreme dimensions of Prelude FLNG and requirements for accuracy of this study called for the CFD calculations to be performed on the High Performance Computing (HPC) clusters - Stampede2 and Frontera - at the Texas Advanced Computing Center (TACC), which are both amongst the world’s largest supercomputers. This paper describes the assumptions and challenges of the CFD study and discusses the results of the main program and various sensitivities. The main conclusions and lessons learnt are also discussed.

Aerodynamics of Urban Maglev vehicles

2012 ◽  
Vol 226 (6) ◽  
pp. 561-567 ◽  
Author(s):  
Colin P Britcher ◽  
John M Wells ◽  
Benoit Renaud ◽  
Thibaut Buvat
Keyword(s):  
Wind Tunnel ◽  
Historical Data ◽  
Aerodynamic Characteristics ◽  
Scale Model ◽  
Wind Environment ◽  
Wind Tunnel Tests ◽  
Low Speed ◽  
Lateral Forces ◽  
Old Dominion University

Some aerodynamic issues affecting low-speed Urban Maglev vehicles are studied, focusing primarily on the effect of ambient winds on levitation electromagnet loads. Aerodynamic characteristics of a representative vehicle are estimated by means of wind tunnel tests of a 1/12th scale model. The wind environment influencing the existing Maglev guideway at Old Dominion University are established from historical data. It is shown that ambient winds, particularly crosswinds, can pose significant challenges, including substantial redistribution of levitation forces among vehicle electromagnets. The development of large lateral forces, particularly at the forward electromagnet stations, may also be of concern.

Wind-tunnel tests of the ERICA tiltrotor optimised air-intake

2018 ◽  
Vol 122 (1251) ◽  
pp. 821-837
Author(s):  
G. Gibertini ◽  
A. Zanotti ◽  
G. Campanardi ◽  
F. Auteri ◽  
D. Zagaglia ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Total Pressure ◽  
Internal Surface ◽  
Scale Model ◽  
Interface Plane ◽  
Shape Optimisation ◽  
Duct Flow ◽  
Flow Distortion ◽  
Wind Tunnel Tests ◽  
Air Intake

ABSTRACTWind-tunnel tests were carried out to evaluate the performance of the Computational Fluid Dynamics (CFD)-based air-intake duct shape optimisation of the European platform tiltrotor ERICA. A 1/2.5 scale model including the nacelle, the external portion of the wing and two interchangeable internal ducts reproducing the baseline and optimised shape were manufactered to be tested in the large wind tunnel of Politecnico di Milano. Moreover, tests were carried out with the model equipped with rotating blade stubs. The comprehensive experimental campaign included tests reproducing different forward flight conditions of the aircraft including cruise and conversion phases. The evaluation of the internal duct performance was carried out by measuring total pressure losses and flow distortion by directional probes at the Aerodynamic Interface Plane (AIP). Additional pressure measurements were carried out on the internal surface of the duct to compare the pressure distributions along the air-intake. The experimental results confirmed that the optimised duct offers significantly improved performance with respect to the baseline configuration not only in cruise, representing the flight condition considered for the CFD optimisation, but also for the conversion condition. In particular, a remarkable reduction of the total pressure drop at the AIP was found with the optimised duct with the only exception for the stubs-on configuration in cruise. Indeed, the present investigation highlighted that the design of the blade stubs, particularly their length, represents a very critical aspect for air-intake performance tests due to significant disturbances that could be induced by the stubs’ wake on the internal duct flow.

scholarly journals Vortex Shedding From Struts in an Annular Exhaust Diffuser

1996 ◽  
Author(s):  
Thomas F. Fric ◽  
Reynaldo Villarreal ◽  
Robert O. Auer ◽  
Michael L. James ◽  
Dincer Ozgur ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Gas Turbine ◽  
Strouhal Number ◽  
Vortex Shedding ◽  
Scale Model ◽  
Bluff Bodies ◽  
Cylinder Wake ◽  
Wind Tunnel Tests ◽  
Full Speed ◽  
Inlet Swirl

Results from scale-model experiments and industrial gas turbine tests show that strut vortex shedding in an annular exhaust diffuser can effectively be modified by adding tapered chord to the struts. The struts are bluff bodies at full-speed, no-load conditions, when inlet swirl is close to 60°. Data from wind tunnel tests show that wake Strouhal number is 0.47, larger than that expected for an isolated cylinder wake. This value of Strouhal number agrees with those measured in full-scale exhaust diffusers. Wind tunnel tests showed that a strut with tapered chord most effectively reduced wake amplitudes and shifted shedding frequency. The tapered strut was also effective in reducing shedding amplitude in a scale-model diffuser. Finally, gas turbine tests employing a tapered strut showed significant reductions in unsteady pressure and noise. A major benefit of strut taper is a reduction of noise by uncoupling of vortex shedding from acoustic resonant response.

scholarly journals A 6-DOFs Hardware-in-the-Loop System for Wind Tunnel Tests of Floating Offshore Wind Turbines

2019 ◽  
Author(s):  
Alessandro Fontanella ◽  
Ilmas Bayati ◽  
Federico Taruffi ◽  
Francesco La Mura ◽  
Alan Facchinetti ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Offshore Wind ◽  
Scale Model ◽  
Hardware In The Loop ◽  
Floating Platform ◽  
Wind Tunnel Tests ◽  
Offshore Wind Turbines ◽  
Floating Offshore Wind Turbines

Abstract This article presents a hardware-in-the-loop (HIL) methodology developed at Politecnico di Milano (PoliMi) to perform wind tunnel tests on floating offshore wind turbines (FOWTs). The 6-DOFs HIL setup is presented, focusing on the main differences with respect to a previous 2-DOFs system. Aerodynamic, rotor and control related loads, physically reproduced by the wind turbine scale model, must be measured in real-time and integrated with the platform numerical model. These forces contribute to couple wind turbine and floating platform dynamics and their correct reproduction is of fundamental importance for the correct simulation of the floating system behavior. The procedure developed to extract rotor loads from the available measurements is presented, discussing its limitations and the possible uncertainties introduced in the results. Results from verification tests in no-wind conditions are presented and analyzed to identify the main uncertainty sources and quantify their effect on the reproduction of the floating wind turbine response to combined wind and waves.

scholarly journals Wind Tunnel Tests of Influence of Boosters and Fins on Aerodynamic Characteristics of the Experimental Rocket Platform

2017 ◽  
Vol 2017 (4) ◽  
pp. 82-102
Author(s):  
Paweł Ruchała ◽  
Robert Placek ◽  
Wit Stryczniewicz ◽  
Jan Matyszewski ◽  
Dawid Cieśliński ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Drag ◽  
Wind Tunnel Test ◽  
Longitudinal Axis ◽  
Aerodynamic Characteristics ◽  
Scale Model ◽  
Wind Tunnel Tests ◽  
Aerodynamic Loads ◽  
Microgravity Experiments ◽  
Image Velocimetry

Abstract The paper presents results of wind tunnel tests of the Experimental Rocket Platform (ERP), which is developed in Institute of Aviation. It is designed as an easy accessible and affordable platform for microgravity experiments. Proposed design enables to perform experiments in microgravity for almost 150 seconds with apogee of about 100 km. The full-scale model of the ERP has been investigated in the T-3 wind tunnel in Institute of Aviation. During the investigation, the aerodynamic loads of the rocket has been measured for the angle of attack up to 10° and the different rotation angle around the longitudinal axis (up to 90°, depending on the configuration). Three configurations has been investigated: • without fins and boosters • with fins and without boosters • with fins and boosters Additionally, the measurements of velocity field around the ERP using the Particle Image Velocimetry (PIV) has been performed. Based on the wind tunnel test, an influence of fins and boosters on aerodynamic characteristics of the rocket has been described. Results of the wind tunnel tests show relatively high contribution of boosters in total aerodynamic drag. Some conclusions concerning performance and stability of the rocket have been presented.

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