scholarly journals Hypersonic Aerodynamic Force Balance Using Micromachined All-Fiber Fabry–Pérot Interferometric Strain Gauges

Micromachines ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 316 ◽  
Author(s):  
Huacheng Qiu ◽  
Fu Min ◽  
Yanguang Yang ◽  
Zengling Ran ◽  
Jinxin Duan
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Force ◽  
High Sensitivity ◽  
Force Balance ◽  
Strain Gauges ◽  
External Temperature ◽  
Thermal Output ◽  
Hypersonic Wind Tunnel ◽  
Wide Range ◽  
Fabry Perot

This paper presents high-sensitivity, micromachined all-fiber Fabry–Pérot interferometric (FFPI) strain gauges and their integration in a force balance for hypersonic aerodynamic measurements. The FFPI strain gauge has a short Fabry–Pérot cavity fabricated using an excimer laser etching process, and the deformation of the cavity is detected by a white-light optical phase demodulator. A three-component force balance, using the proposed FFPI gauges as sensing elements, was fabricated, calibrated, and experimentally evaluated. To reduce thermal output of the balance, a simple and effective self-temperature compensation solution, without external temperature sensors, is proposed and examined through both oven heating and wind tunnel runs. As a result of this approach, researchers are able to use the balance continuously throughout a wide range of temperatures. During preliminary testing in a hypersonic wind tunnel with a free stream Mach number of 12, the measurement accuracies of the balance were clearly improved after applying the temperature self-compensation.

Feasibility investigation of large-scale model suspended by cable-driven parallel robot in hypersonic wind tunnel test

2016 ◽  
Vol 231 (13) ◽  
pp. 2375-2383 ◽  
Author(s):  
Xiaoguang Wang ◽  
Miaojiao Peng ◽  
Zhenghong Hu ◽  
Yueshi Chen ◽  
Qi Lin
Keyword(s):  
Wind Tunnel ◽  
Large Scale ◽  
Cfd Simulation ◽  
Aerodynamic Force ◽  
Wind Tunnel Test ◽  
Special Kind ◽  
Parallel Robot ◽  
Scale Model ◽  
Hypersonic Wind Tunnel ◽  
Large Scale Model

Cable-driven parallel robot is a special kind of robot, which is actuated by cables. It is already applied in the low speed wind tunnel to get aerodynamic measurement of aircraft model, and the aircraft pose could be adjusted by changing the cable length. Whether it can be used in hypersonic wind tunnel still needs further discussion. This paper presents the dynamics and aerodynamics analysis of a large-scale model supported by 6-DOF cable-driven parallel robot to investigate the feasibility of this special kind of suspension system in hypersonic wind tunnel. The description of this setup with a X-51A-like model is given, and then based on the system dynamic equations, aerodynamic force and stiffness matrix are derived. In the simulation, properties of dynamics and aerodynamics are mainly concerned. A typical shock tunnel with flow duration of about 100 milliseconds is taken as an example, and results show that the system is stable enough to meet the fundamental static wind tunnel test. From the cable tension variation under impact load and the sensitivity analysis, it is likely accessible to derive the aerodynamic forces. Compared with the sting suspension method, cable-driven parallel robot has the priority of higher inherent frequency and more flexible degrees. The interference to the flow field induced by cables is also preliminarily proved to be small by the CFD simulation, which can be acceptable and corrected. Researches conducted show the feasibility of cable-driven parallel robot’s application in hypersonic wind tunnel.

scholarly journals Quantitative characterization reveals three types of dry-sensitive corneal afferents: pattern of discharge, receptive field, and thermal and chemical sensitivity

2012 ◽  
Vol 108 (9) ◽  
pp. 2481-2493 ◽  
Author(s):  
Harumitsu Hirata ◽  
Nathan Fried ◽  
Michael L. Oshinsky
Keyword(s):  
Receptive Fields ◽  
High Sensitivity ◽  
Stimulus Onset ◽  
High Threshold ◽  
Heat Sensitivity ◽  
Noxious Heat ◽  
External Temperature ◽  
Wide Range ◽  
Highly Correlated ◽  
Discharge Patterns

This study reveals that the cold-sensitive (CS) + dry-sensitive (DS) corneal afferents reported in a previous study consist of two types: 1) low threshold (LT)-CS + DS neurons with <1°C cooling sensitivity, and 2) high threshold (HT)-CS + DS neurons with a wide range of cooling sensitivities (∼1–10°C cooling). We also found DS neurons with no cooling sensitivity down to 19°C [cold-insensitive (CI) + DS neurons]. LT-CS + DS neurons showed highly irregular discharge patterns during the dry cornea characterized by numerous spiking bursts, reflecting small temperature changes in the cornea. Their receptive fields (RFs) were mainly located in the cornea's center, the first place for tears to ebb from the surface and be susceptible to external temperature fluctuations. HT-CS and CI + DS neurons showed a gradual rise in firing rate to a stable level over ∼60 s after the dry stimulus onset. Their RFs were located mostly in the cornea's periphery, the last place for tears to evaporate. The exquisite sensitivity to cooling in LT-CS + DS neurons was highly correlated with heat sensitivity (∼45°C). There was a perfect correlation between noxious heat sensitivity and capsaicin responsiveness in each neuron type. The high sensitivity to noxious osmotic stress was a defining property of the HT-CS and CI + DS neurons, while high sensitivity to menthol was a major characteristic of the LT-CS + DS neurons. These observations suggest that three types of DS neurons serve different innocuous and nociceptive functions related to corneal dryness.

A Wind Tunnel Study Of The Interaction Between Two Sailing Yachts

2013 ◽  
Author(s):  
P. J. Richards ◽  
D. J. Le Pelley ◽  
D. Jowett ◽  
J. Little ◽  
O. Detlefsen
Keyword(s):  
Wind Tunnel ◽  
Test Section ◽  
Force Measurement ◽  
Aerodynamic Force ◽  
Force Balance ◽  
The Other ◽  
Flow Disturbance ◽  
Negative Interference ◽  
Wind Tunnel Study

The interference between two yachts sailing in several conditions is investigated in the wind tunnel by using two similar yacht models, one of which is mounted on a force balance and the other moved around the test section. The yachts were configured to sail close-hauled upwind at 20° apparent wind angle, downwind under asymmetric spinnaker at 60° and downwind under symmetric spinnaker at 120° apparent wind angle. The regions of positive and negative interference are determined through aerodynamic force measurement and flow disturbance measurement, and the sources of these effects investigated.

scholarly journals Aerodynamic analysis of aircraft model using indigenously developed wind tunnel facility

2021 ◽  
Vol 1206 (1) ◽  
pp. 012013
Author(s):  
D Makhija ◽  
S V Jain ◽  
A M Achari ◽  
K Ghosh
Keyword(s):  
Wind Tunnel ◽  
Lift Force ◽  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Angle Of Attack ◽  
Open Circuit ◽  
Force Balance ◽  
Number Range ◽  
Aircraft Model ◽  
Wide Range

Abstract This paper presents a design of force balance setup that can measure lift force acting on the aircraft model. The setup was developed indigenously and installed in an open circuit low-speed wind tunnel. It mainly consists of two components viz. a traverse mechanism that can hold the model in the test section at different angles of attack and air speeds and a supporting frame to hold the traverse mechanism over it. The spring balances are used to obtain lift force readings at different angles and air speeds. The experimental and numerical investigations were done in the wide range of Reynolds number (range: 0.55 to 1.12 lakh) and angle of attack (range: -6° to 20°). The results are presented in terms of pressure contours, velocity contours, pressure coefficient and lift coefficient. From the experiments it was found that value of lift coefficient increases with angle of attack and stalling occurs at 18° for all the air speeds. However, in the numerical results the stalling was observed little earlier than 18° angle of attack. The experimental results were compared with CFD results and an average relative error of 18% was observed which may be due to assumption of 2-D airfoil in CFD analysis.

Wind Tunnel Test on Wind-Induced Aerodynamic Force of Transmission Tower

2014 ◽  
Vol 578-579 ◽  
pp. 427-431
Author(s):  
Wen Shan Shan ◽  
Bo Li ◽  
Jing Bo Yang ◽  
Yang Liu
Keyword(s):  
Wind Tunnel ◽  
Power Transmission ◽  
Aerodynamic Force ◽  
Wind Tunnel Test ◽  
Force Balance ◽  
Test Results ◽  
Transmission Tower ◽  
Balance Test ◽  
Shape Coefficient ◽  
Wind Speeds

Wind-induced aerodynamic force is the important parameter for transmission tower design. Based on force balance test, the tower and cross arm of typical 500kV power transmission tower have been investigated in wind tunnel using three wind speeds considering Reynolds effect. The test results show that the shape coefficient keeps the same at different wind speed, which means that Reynolds effect on transmission tower can be ignored. Then, the shape coefficients of tower and cross arm are provided.

DETERMINATION OF MATERIAL CATALYCITY AT HIGH TEMPERATURES IN THE VAT-104 HYPERSONIC WIND TUNNEL

2014 ◽  
Vol 45 (1) ◽  
pp. 3-20 ◽  
Author(s):  
Ivan Vladimirovich Egorov ◽  
Boris Evgen'evich Zhestkov ◽  
Vladimir Viktorovich Shvedchenko
Keyword(s):  
Wind Tunnel ◽  
High Temperatures ◽  
Hypersonic Wind Tunnel

Extremely Gusty Winds from a Viewpoint of Aerodynamic Force

2020 ◽  
Author(s):  
Junji Maeda ◽  
Takashi Takeuchi ◽  
Eriko Tomokiyo ◽  
Yukio Tamura
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Rise Time ◽  
Aerodynamic Force ◽  
Step Function ◽  
Object Size ◽  
Aerodynamic Forces ◽  
Wind Force ◽  
Wind Observation

To quantitatively investigate a gusty wind from the viewpoint of aerodynamic forces, a wind tunnel that can control the rise time of a step-function-like gust was devised and utilized. When the non-dimensional rise time, which is calculated using the rise time of the gusty wind, the wind speed, and the size of an object, is less than a certain value, the wind force is greater than under the corresponding steady wind. Therefore, this wind force is called the “overshoot wind force” for objects the size of orbital vehicles in an actual wind observation. The finding of the overshoot wind force requires a condition of the wind speed recording specification and depends on the object size and the gusty wind speed.

scholarly journals Gold–Carbon Nanocomposites for Environmental Contaminant Sensing

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 719
Author(s):  
Shahrooz Rahmati ◽  
William Doherty ◽  
Arman Amani Babadi ◽  
Muhamad Syamim Akmal Che Mansor ◽  
Nurhidayatullaili Muhd Julkapli ◽  
...  
Keyword(s):  
Environmental Pollutants ◽  
High Sensitivity ◽  
Environmental Crisis ◽  
World Population ◽  
Chemical Contaminants ◽  
Carbon Nanocomposites ◽  
Minimal Sample ◽  
Wide Range ◽  
And Control ◽  
Analytical Tools

The environmental crisis, due to the rapid growth of the world population and globalisation, is a serious concern of this century. Nanoscience and nanotechnology play an important role in addressing a wide range of environmental issues with innovative and successful solutions. Identification and control of emerging chemical contaminants have received substantial interest in recent years. As a result, there is a need for reliable and rapid analytical tools capable of performing sample analysis with high sensitivity, broad selectivity, desired stability, and minimal sample handling for the detection, degradation, and removal of hazardous contaminants. In this review, various gold–carbon nanocomposites-based sensors/biosensors that have been developed thus far are explored. The electrochemical platforms, synthesis, diverse applications, and effective monitoring of environmental pollutants are investigated comparatively.

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