Wind tunnel test of a full-scale heliostat

Abstract Assessing the aerodynamic characteristics of long-span bridges is fundamental for their design. Depending on the terrain complexity and local wind conditions, episodes of large angles of attack (AoA) of 15° may be observed. However, such large AoAs ( above 10°) are often overlooked in the design process. This paper studies the aerodynamics properties of a flow around a single-box girder for a wide range of AoAs, from –20° to 20°, using numerical simulations. The simulations are based on a 2D unsteady Reynolds-averaged Navier–Stokes (URANS) approach using the k − ω SST turbulence model with a Reynolds number of 1.6 × 105. Numerically obtained aerodynamic static coefficients were compared to wind tunnel test data. The CFD results were generally in good agreement with the wind tunnel tests, especially for small AoAs and positive AoAs. More discrepancies were observed for large negative AoA, likely due to the limitation of modelling 3D railings with 2D simulations. The simulated velocity deficit downstream of the deck was consistent with the one measured in full-scale using short-range Doppler wind lidar instruments. Finally, the Strouhal number from the CFD simulations were in agreement with the value obtained from the full-scale data.

Download Full-text

Scaling Method of the Rotating Blade of a Wind Turbine for a Rime Ice Wind Tunnel Test

Energies ◽

10.3390/en12040627 ◽

2019 ◽

Vol 12 (4) ◽

pp. 627 ◽

Cited By ~ 3

Author(s):

Yan Li ◽

Ce Sun ◽

Yu Jiang ◽

Fang Feng

Keyword(s):

Heat Transfer ◽

Wind Tunnel ◽

Large Scale ◽

Wind Tunnel Test ◽

Full Scale ◽

Similar Degree ◽

Transfer Model ◽

Ice Accretion ◽

Water Droplets ◽

Scaling Method

In order to research the law of rime ice accretion on different scaling blades surface, a new rime ice scaling method was proposed in this research. According to previous research, there are three kinds of ice types on blade surfaces: rime ice, glaze ice and mixed ice. Under the condition of rime ice, both the freezing fraction and the coefficient of heat transfer between super-cold water droplets and blade are 100%. The heat transfer model of rime ice is simpler than that of glaze ice and mixed ice. In this research, the scaling parameters including flow field, water droplets, temperature, pressure and rotating parameters were defined. The Weber number (We) based on water film thickness as an important parameter was applied in this study. The rotating parameters including rotating speed and radius had been added into the icing scaling method. To verify the effectiveness of the new rime ice scaling method, icing wind tunnel tests were carried out. The NACA0018 airfoil was used for the test blade. Two kinds of scale chord blades were selected, the chord of full-scale blade was 200 mm and of subscale blade was 100 mm. The test temperature was −15 °C. The ice accretion on different scale blades surface were captured by high-speed camera and the icing shapes of different scaling blades were obtained. To quantitatively analyze the similar degree of icing shapes on different scale blades, an evaluation method which included similar degree (Sim) was established based on the typical characteristic parameters proposed by previous research. The results show that the icing shapes of subscale blades are similar to that of full-scale blades. The similar degree is between 75.22% and 93.01%. The icing wind tunnel test indicates that the new rime ice scaling method is an effective method to study the rime ice of large scale rotating blades. This study can be used as a reference for research on anti-icing and de-icing technologies for large-scale HAWTs (Horizontal Axis Wind Turbines).

Download Full-text

A full-scale prediction method for wind turbine rotor noise by using wind tunnel test data

Renewable Energy ◽

10.1016/j.renene.2013.09.032 ◽

2014 ◽

Vol 65 ◽

pp. 257-264 ◽

Cited By ~ 14

Author(s):

Jaeha Ryi ◽

Jong-Soo Choi ◽

Seunghoon Lee ◽

Soogab Lee

Keyword(s):

Wind Tunnel ◽

Wind Turbine ◽

Test Data ◽

Wind Tunnel Test ◽

Prediction Method ◽

Turbine Rotor ◽

Full Scale ◽

Rotor Noise ◽

Wind Turbine Rotor

Download Full-text

Wind tunnel test analysis to determine pantograph noise contribution on a high-speed train

Advances in Mechanical Engineering ◽

10.1177/1687814019884778 ◽

2019 ◽

Vol 11 (10) ◽

pp. 168781401988477

Author(s):

Hee-Min Noh

Keyword(s):

Wind Tunnel ◽

Noise Reduction ◽

High Speed ◽

Acoustic Noise ◽

Microphone Array ◽

Wind Tunnel Test ◽

Full Scale ◽

Scale Model ◽

Test Analysis ◽

Noise Contribution

In this study, we investigated the characteristics and the influence of the aero-acoustic noise generated from a pantograph using various experimental approaches in a wind tunnel. First, the noise generated at various flow velocities was measured and analyzed using a full-scale pantograph model. Then, the noise generated from the main position of the pantograph was derived using a microphone array attached to one side of a wind tunnel. The noise contributions of the main components of the pantograph were derived from the noise measurements obtained from a step-by-step disassembly of the full-scale model. In addition, the noise reduction achieved by panhead collectors, which are some of the most important noise sources on a pantograph, was examined by studying the results obtained when varying their geometry. In order to analyze the noise-reduction effect achieved by varying the height of the collector, different types of collectors were fabricated and wind tunnel tests were conducted. Through this study, we have investigated the aero-acoustic noise contribution of the major components of a pantograph, and we have developed effective noise-reduction measures for the panhead collector.

Download Full-text

Pressure Distributions on Sails Investigated Using Three Methods: On-Water Measurements, Wind-Tunnel Measurements, and Computational Fluid Dynamics

10.5957/csys-2011-004 ◽

2011 ◽

Author(s):

Ignazio Maria Viola ◽

Richard G. J. Flay

Keyword(s):

Wind Tunnel ◽

Wind Tunnel Test ◽

Full Scale ◽

Navier Stokes ◽

Pressure Measurements ◽

Wind Tunnel Tests ◽

Pressure Distributions ◽

Unstable Environment ◽

Full Scale Tests ◽

Good Agreement

The main results of a two-year project aimed at comparing full-scale tests, wind tunnel tests, and numerical analysis predictions are presented. Pressure measurements were obtained from both full-scale tests and wind-tunnel tests, in upwind and downwind conditions. The upwind wind tunnel test condition was modelled using a Vortex Lattice code, while the downwind wind-tunnel test was modelled using a Navier-Stokes code. The pressures obtained from the three different methods are compared on three horizontal sections of the headsail, mainsail, and asymmetric spinnaker. In general the pressures from the three experiments showed good agreement. In particular, very good agreement was obtained between the numerical computations and the wind tunnel test results. Conversely, the results from the downwind full-scale pressure measurements showed less similarity due to a slightly tightened trim being used for the spinnaker in the on-water tests. Full-scale tests allow the action of unsteadiness due to the wind, wave and yacht movements to affect the results. This unstable environment caused the asymmetric spinnaker to move around, and a tightened trim was required to prevent the spinnaker from collapsing.

Download Full-text