Accurate determination of reference wind speed and reference static pressure in wind tunnel tests

2019 ◽  
Vol 23 (3) ◽  
pp. 578-583
Author(s):  
YC He ◽  
JCK Cheung ◽  
QS Li ◽  
JY Fu
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Measurement Method ◽  
Static Pressure ◽  
Accurate Determination ◽  
Indirect Measurement ◽  
Measurement Methods ◽  
Wind Tunnel Experiments

The reference wind speed and reference static pressure are two key parameters for determining the testing results of wind tunnel experiments. Traditionally, the values of these parameters can be determined using direct measurement methods. However, such methods may suffer from less accuracy and inconvenience of operations. This article documents an indirect measurement method which, compared to the traditional methods, has the merits of higher accuracy and greater operational convenience. Examples are presented to demonstrate the main procedures of the method and typical findings by using the method in a boundary layer wind tunnel.

scholarly journals Design of a Wind Sensor Based on Cylinder Diametrical Pressure Differences for Boundary Layer Meteorological Observation

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 1511
Author(s):  
Zhan Zhao ◽  
Yichen Pan ◽  
Rongjian Zhao ◽  
Lidong Du ◽  
Zhen Fang ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Pressure Difference ◽  
Pressure Sensors ◽  
Differential Pressure ◽  
Two Dimensional ◽  
Relative Speed ◽  
Meteorological Observation ◽  
Wind Tunnel Experiments

Wind speed and direction are important parameters in meteorological observation. Solid wind sensor has needed with small Quadcopter for boundary layer meteorological observation. In this paper the principle of a cylindrical two-dimensional wind sensor is reported by analyzing the data from wind tunnel experiments. A model is proposed to describe the distribution of the pressure difference across a diameter of a cylinder and the wind sensor is fabricated with MEMS differential pressure sensors. In wind tunnel tests in range of 1~40 m/s, the relative speed measuring errors and the direction measuring errors of the prototype are no more than ±(0.2 + 0.03 V) m/s and 5° respectively.

scholarly journals High Accuracy and Miniature 2-D Wind Sensor for Boundary Layer Meteorological Observation

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1194 ◽  
Author(s):  
Yichen Pan ◽  
Zhan Zhao ◽  
Rongjian Zhao ◽  
Zhen Fang ◽  
Hong Wu ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Measurement Accuracy ◽  
Pressure Sensors ◽  
Micro Electro Mechanical System ◽  
High Accuracy ◽  
Relative Speed ◽  
Meteorological Observation ◽  
Wind Tunnel Experiments

Wind speed and direction are important parameters in meteorological observation. A solid wind sensor is needed with a small quadcopter for boundary layer meteorological observation. In this paper, the principle of a cylindrical two-dimensional wind sensor is reported and the data from wind tunnel experiments are analyzed. A model is proposed to describe the distribution of the pressure difference across a diameter of a cylinder, and the wind sensor is fabricated with MEMS (Micro-Electro-Mechanical System) differential pressure sensors. The wind sensor cylinder has a small size with a diameter of 30 mm and a height of 80 mm. In wind tunnel tests in the range of 1 to 40 m/s, the relative speed measuring errors and the direction measuring errors of the prototype are no more than ± (0.2 + 0.03 V) m/s (V is standard wind speed) and 5°, respectively. An inclination angle model is proposed to correct the influence of tilt angle on the quadcopter platform, the wind sensor can maintain the original wind speed and direction measurement accuracy within the 30° inclination range after compensation.

scholarly journals Experimental Investigation of a Prandtl Probe Fabricated Using Desktop Stereolithography Technology

2020 ◽  
Vol 5 (10) ◽  
pp. 1274-1280
Author(s):  
Alfred Gift Mwachugha ◽  
Jean Byiringiro ◽  
Harrison Ngetha ◽  
Thomas Carolus ◽  
Kathrin Stahl
Keyword(s):  
Additive Manufacturing ◽  
Wind Tunnel ◽  
Accurate Determination ◽  
Wind Tunnels ◽  
Research Institution ◽  
Flow Characterization ◽  
Desktop Manufacturing ◽  
Flow Quality ◽  
Manufacturing Platform

A Prandtl probe is one of the standard instruments used for flow characterization in wind tunnel facilities. The convectional fabrication method of this instrument requires skilled artisanship, precision drilling, lathing and soldering of its several parts. This reflects into high costs of production in turn making wind energy studies expensive. With the adoption of additive manufacturing, the tooling costs, skills required and design to manufacture constraints can be addressed. This research presents a Prandtl probe that was designed using NX™ software, fabricated by desktop stereolithography additive manufacturing platform and validated in a wind tunnel for velocity range of 0 m/s to 51 m/s. This research attested the option of fabricating relatively cheap functional Prandtl probe with desktop stereolithography technology which can be used for accurate determination of flow quality in wind tunnels experiments. This provides various learning and research institution in developing countries that have already invested in additive desktop manufacturing technology certainty and a cheaper option to fabricate wind research instruments for use at their laboratories. Moreover, fabrication and validation of a 5-hole Prandtl probe can also be examined.

scholarly journals Investigation of the Superposition Effect of Oil Vapor Leakage and Diffusion from External Floating-Roof Tanks Using CFD Numerical Simulations and Wind-Tunnel Experiments

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 299
Author(s):  
Jie Fang ◽  
Weiqiu Huang ◽  
Fengyu Huang ◽  
Lipei Fu ◽  
Gao Zhang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Simulation Method ◽  
Vapor Concentration ◽  
Monitoring And Control ◽  
Wind Tunnel Experiments ◽  
Ambient Wind ◽  
Wind Speeds ◽  
High Concentrations ◽  
And Control

Based on computational fluid dynamics (CFD) and Realizable k-ε turbulence model, we established a numerical simulation method for wind and vapor-concentration fields of various external floating-roof tanks (EFRTs) (single, two, and four) and verified its feasibility using wind-tunnel experiments. Subsequently, we analysed superposition effects of wind speed and concentration fields for different types of EFRTs. The results show that high concentrations of vapor are found near the rim gap of the floating deck and above the floating deck surface. At different ambient wind speeds, interference between tanks is different. When the ambient wind speed is greater than 2 m/s, vapor concentration in leeward area of the rear tank is greater than that between two tanks, which makes it easy to reach explosion limit. It is suggested that more monitoring should be conducted near the bottom area of the rear tank and upper area on the left of the floating deck. Superposition in a downwind direction from the EFRTs becomes more obvious with an increase in the number of EFRTs; vapor superposition occurs behind two leeward tanks after leakage from four large EFRTs. Considering safety, environmental protection, and personnel health, appropriate measures should be taken at these positions for timely monitoring, and control.

The pressure-hole problem

1984 ◽  
Vol 142 ◽  
pp. 251-267 ◽  
Author(s):  
C. Ducruet ◽  
A. Dyment
Keyword(s):  
Boundary Layer ◽  
Incompressible Flow ◽  
Velocity Gradient ◽  
Static Pressure ◽  
Slender Body ◽  
Complex Flows ◽  
Dimensionless Parameters ◽  
Pressure Drag ◽  
Partial Linearization

The static pressure-hole problem is investigated both theoretically and experimentally. The influence of all significant dimensionless parameters is brought to light. These parameters represent the effects of the boundary layer, of the velocity gradient and of the wall curvature. A partial linearization makes it possible to propose a formula of correction containing three influence functions which cannot be determined by the theory. A limited number of experiments on appropriate models leads to the determination of these functions in case of practical requirements. So, a method of correction is obtained, but only in incompressible flow. The previous formula has been verified in two complex flows. The importance of the correction on the pressure drag of a slender body is brought to light and the difficulties in the application on the method are emphasized.

Experimental investigation of aerodynamic vibrations of solar wing system

2018 ◽  
Vol 21 (15) ◽  
pp. 2217-2226 ◽  
Author(s):  
YC Kim ◽  
Y Tamura ◽  
A Yoshida ◽  
T Ito ◽  
W Shan ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Experimental Investigation ◽  
Wind Speed ◽  
Wind Tunnel ◽  
Solar Panels ◽  
Boundary Layer Flows ◽  
Turbulence Flow ◽  
Aeroelastic Model ◽  
Mean Wind Speed ◽  
The Mean

The general characteristics of aerodynamic vibrations of a solar wing system were investigated through wind tunnel tests using an aeroelastic model under four oncoming flows. In total, 12 solar panels were suspended by cables and orientated horizontally. Distances between panels were set constant. Tests showed that the fluctuating displacement increases proportionally to the square of the mean wind speed for all wind directions in boundary-layer flows. Larger fluctuating displacements were found for boundary-layer flows with larger power-law indices. Under low-turbulence flow, the fluctuating displacement increased proportionally to the square of the mean wind speed for wind directions between 0° and 30°, but an instability vibration was observed at high mean wind speed for wind directions larger than 40°. And when the wind direction was larger than 60°, a limited vibration was observed at low mean wind speed and the instability vibration was also observed at high mean wind speed. Fluctuating displacements under grid-generated flow showed a similar trend to that of the boundary-layer flows, although the values became much smaller.

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