An experimental study of a plasma actuator in absence of free airflow: Ionic wind velocity profile

2010 ◽  
Vol 17 (8) ◽  
pp. 083503 ◽  
Author(s):  
R. Mestiri ◽  
R. Hadaji ◽  
S. Ben Nasrallah
Keyword(s):  
Experimental Study ◽  
Velocity Profile ◽  
Wind Velocity ◽  
Plasma Actuator ◽  
Ionic Wind

A numerical approach for the assessment of crosswind effects on barrier-protected trains running on bridges

2021 ◽  
Author(s):  
Giuseppe Porpiglia ◽  
Paolo Schito ◽  
Tommaso Argentini ◽  
Alberto Zasso
Keyword(s):  
Wind Tunnel ◽  
Velocity Profile ◽  
Wind Velocity ◽  
Aerodynamic Force ◽  
Numerical Approach ◽  
Aerodynamic Performance ◽  
Vehicle Speed ◽  
Initial Condition ◽  
Cfd Analyses ◽  
Moving Train

<p>This paper introduces a new methodology to assess the influence of a windscreen on the crosswind performance of trains running on a bridge. Considering the difficulties encountered in both carrying out wind tunnel tests that consider the vehicle speed or complete CFD analyses, a simplified CFD approach is here discussed. Instead of simulating simultaneously the windscreen plus the moving train, the numerical problem is split into two parts: firstly, a simulation of the windshield alone is used to extract the perturbed velocity profile at the railway location; secondly, this profile used as an inlet condition for the wind velocity acting on an isolated train. The method is validated against a complete train plus windshield simulation in terms of pressure distribution and aerodynamic force coefficients on the train, and flow streamlines. This approach opens to the possibility of evaluating the aerodynamic performance of a vehicle on bridges considering bridge and vehicle as separated. Wind velocity profiles measured on the bridge during a wind tunnel campaign could be used as the initial condition for numerical simulations on vehicles.</p>

scholarly journals Experimental Study of the Jet Engine Exhaust Flow Field of Aircraft and Blast Fences

2015 ◽  
Vol 27 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Haifu Wang ◽  
Liangcai Cai ◽  
Xiaolei Chong ◽  
Hao Geng
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Wind Velocity ◽  
Maximum Rate ◽  
Dynamic Pressure ◽  
Jet Flow ◽  
Engine Exhaust ◽  
Jet Engine ◽  
Jet Nozzle

A combined blast fence is introduced in this paper to improve the solid blast fences and louvered ones. Experiments of the jet engine exhaust flow (hereinafter jet flow for short) field and tests of three kinds of blast fences in two positions were carried out. The results show that the pressure and temperature at the centre of the jet flow decrease gradually as the flow moves farther away from the nozzle. The pressure falls fast with the maximum rate of 41.7%. The dynamic pressure 150 m away from the nozzle could reach 58.8 Pa, with a corresponding wind velocity of 10 m/s. The temperature affected range of 40°C is 113.5×20 m. The combined blast fence not only reduces the pressure of the flow in front of it but also solves the problems that the turbulence is too strong behind the solid blast fences and the pressure is too high behind the louvered blast fences. And the pressure behind combined blast fence is less than 10 Pa. The height of the fence is related to the distance from the jet nozzle. The nearer the fence is to the nozzle, the higher it is. When it is farther from the nozzle, its height can be lowered.

scholarly journals Experimental Study on Anti-Icing Performance of NS-DBD Plasma Actuator

2018 ◽  
Vol 8 (10) ◽  
pp. 1889 ◽  
Author(s):  
Jie Chen ◽  
Hua Liang ◽  
Yun Wu ◽  
Biao Wei ◽  
Guangyin Zhao ◽  
...  
Keyword(s):  
Experimental Study ◽  
Heat Dissipation ◽  
Ccd Camera ◽  
Liquid Water Content ◽  
Pulse Frequency ◽  
Plasma Actuator ◽  
Voltage Amplitude ◽  
Dbd Plasma ◽  
Naca0012 Airfoil ◽  
Actuation Signal

An experimental study was conducted to evaluate the anti-icing performance of NS-DBD plasma actuator under the conditions of airflow speed U = 65 m/s, ambient temperature T = −10 °C, liquid water content LWC = 0.5 g/m3, mean-volume diameter MVD = 25 μm, mainly to clarify the effect of pulse frequency and voltage amplitude of actuation on anti-icing performance. A NACA0012 airfoil model with a chord length of c = 280 mm was used in the tests. The NS-DBD plasma actuator was mounted at the front part of the airfoil. A FLIR infrared (IR) imager and CCD camera were used to record the anti-icing process of the NS-DBD plasma actuator. Two typical discharge conditions were selected for the anti-icing experiments. The first was HV-LF discharge, corresponding to discharge under higher voltage amplitude with lower pulse frequency; the second was LV-HF discharge, corresponding to discharge under lower voltage amplitude with higher pulse frequency. Results reveal that NS-DBD is a very promising method for anti-icing. With the same power consumption, the LV-HF discharge shows a better anti-icing performance compared to HV-LF discharge under the same icing conditions. In view of pulse duration and duty circle, combined with heat dissipation, it is suggested that there is a threshold frequency, corresponding to the voltage amplitude of electric actuation signal and the incoming flow condition, to achieve effective anti-icing performance.

On strong blowing into an incompressible airstream

1973 ◽  
Vol 60 (2) ◽  
pp. 241-255 ◽  
Author(s):  
F. T. Smith
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Velocity Profile ◽  
Air Injection ◽  
Relative Mass ◽  
Pressure Measurements ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Strong Injection ◽  
Steady Laminar

An experimental study of distributed air-injection from a porous section of a flat plate into a uniform incompressible airflow is described. The relative mass flow rates of the injection varied between 0·008 and 0·053 (strong injection) and the blowing was fairly uniformly distributed. In the resulting flow field, which was predominantly laminar except near the dividing streamline, where unsteadiness prevailed, velocity profile and pressure measurements were taken and the position of the dividing streamline thereby estimated. Overall the results agree fairly well with the steady laminar theory for strong normal blowing, outlined in §2, although for the strongest blow some signs of separation some way upstream of the blow are apparent.

Passive A-band Wind Sounder (PAWS) for measuring tropospheric wind velocity profile

2007 ◽  
Author(s):  
Grzegorz Miecznik ◽  
Robert Pierce ◽  
Pei Huang ◽  
Philip A. Slaymaker ◽  
Paul Kaptchen ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Wind Velocity ◽  
Tropospheric Wind
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