scholarly journals Reducing of Pressure Based Drag Force of a Bus Model by Flow Control Rod in Wind Tunnel

2021 ◽  
Author(s):  
Cihan BAYINDIRLI
Keyword(s):  
Wind Tunnel ◽  
Flow Control ◽  
Drag Force ◽  
Control Rod

Experimental Study of Flow Control Over a Standard Road Vehicle Using Plasma Actuator

2020 ◽  
Vol 22 (4) ◽  
pp. 1047-1060
Author(s):  
S. Shadmani ◽  
S. M. Mousavi Nainiyan ◽  
R. Ghasemiasl ◽  
M. Mirzaei ◽  
S. G. Pouryoussefi
Keyword(s):  
Flow Control ◽  
Pressure Distribution ◽  
Drag Force ◽  
Separated Flow ◽  
Plasma Actuator ◽  
Road Vehicle ◽  
Slant Angle ◽  
Total Drag ◽  
Slant Surface ◽  
Ahmed Body

AbstractAhmed Body is a standard and simplified shape of a road vehicle that's rear part has an important role in flow structure and it's drag force. In this paper flow control around the Ahmed body with the rear slant angle of 25° studied by using the plasma actuator system situated in middle of the rear slant surface. Experiments conducted in a wind tunnel in two free stream velocities of U = 10m/s and U = 20m/s using steady and unsteady excitations. Pressure distribution and total drag force were measured and smoke flow visualization carried out in this study. The results showed that at U = 10m/s using plasma actuator suppress the separated flow over the rear slant slightly and be effective on pressure distribution. Also, total drag force reduces in steady and unsteady excitations for 3.65% and 2.44%, respectively. At U = 20m/s, using plasma actuator had no serious effect on the pressure distribution and total drag force.

Aerodynamics of Cyclist Posture, Bicycle and Helmet Characteristics in Time Trial Stage

2012 ◽  
Vol 28 (3) ◽  
pp. 317-323 ◽  
Author(s):  
Vincent Chabroux ◽  
Caroline Barelle ◽  
Daniel Favier
Keyword(s):  
Statistical Analysis ◽  
Wind Tunnel ◽  
Drag Coefficient ◽  
Drag Force ◽  
Time Trial ◽  
Frontal Area ◽  
Significant Gain ◽  
Upper Limbs ◽  
Force Coefficient ◽  
Coefficient Reduction

The present work is focused on the aerodynamic study of different parameters, including both the posture of a cyclist’s upper limbs and the saddle position, in time trial (TT) stages. The aerodynamic influence of a TT helmet large visor is also quantified as a function of the helmet inclination. Experiments conducted in a wind tunnel on nine professional cyclists provided drag force and frontal area measurements to determine the drag force coefficient. Data statistical analysis clearly shows that the hands positioning on shifters and the elbows joined together are significantly reducing the cyclist drag force. Concerning the saddle position, the drag force is shown to be significantly increased (about 3%) when the saddle is raised. The usual helmet inclination appears to be the inclination value minimizing the drag force. Moreover, the addition of a large visor on the helmet is shown to provide a drag coefficient reduction as a function of the helmet inclination. Present results indicate that variations in the TT cyclist posture, the saddle position and the helmet visor can produce a significant gain in time (up to 2.2%) during stages.

Wind Tunnel Experiment of Microjet-based Flow Control on a Multi-Element High-Lift Airfoil

2022 ◽  
Author(s):  
Case P. Van Dam ◽  
Sai B. Mothukuri ◽  
Seyedeh Sheida Hosseini ◽  
Edward White ◽  
Lisa Brown ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Flow Control ◽  
Wind Tunnel Experiment ◽  
High Lift

scholarly journals Aerodynamic Performance of Road Vehicles

2020 ◽  
Vol 9 (6) ◽  
pp. 642-645
Keyword(s):  
Wind Tunnel ◽  
Drag Force ◽  
Aerodynamic Drag ◽  
Aerodynamic Performance ◽  
Polished Surface ◽  
Anova Analysis ◽  
Road Vehicles ◽  
Car Model ◽  
Group Data ◽  
Scale Models

Aerodynamic drag has been experimentally estimated for scale models of a passenger car and a commercial truck in a wind tunnel. Polished surface has resulted up to 15 % reduction in drag force and add-on has resulted in 57% increase in drag force of a car model whereas 2.6 % reduction in drag force has resulted by using deflector in a commercial truck model. Anova analysis shows variation in mean of group data.

Suppression of Wind Tunnel Buffeting by Active Flow Control

2004 ◽  
Author(s):  
Wilhelm von Heesen ◽  
Matthias Höpfer
Keyword(s):  
Wind Tunnel ◽  
Flow Control ◽  
Active Flow Control ◽  
Active Flow

An Environmental Wind Tunnel Facility for Testing Meteorological Sensor Systems

2014 ◽  
Vol 31 (2) ◽  
pp. 447-457 ◽  
Author(s):  
C. Holstein-Rathlou ◽  
J. Merrison ◽  
J. J. Iversen ◽  
A. B. Jakobsen ◽  
R. Nicolajsen ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Flow Control ◽  
Extreme Environments ◽  
Research Community ◽  
Future Research ◽  
Wind Flow ◽  
Sensor Systems ◽  
Sensing Systems ◽  
Research Activities ◽  
Controlled Conditions

Abstract Reliable and accurate environmental sensing is a cornerstone of modern meteorology. This paper presents a laboratory environmental simulator capable of reproducing extreme environments and performing tests and calibrations of meteorological sensor systems under controlled conditions. This facility is available to the research community as well as industry and is intended to encourage advancement in the field of sensor metrology applied to meteorology and climatology. Discussion will be made of the temperature, pressure, humidity and wind flow control, and sensing systems with reference to specific sensor test programs and future research activities.

Development of a Surface Flow Sensor for Measuring Turbulent Drag Force

2019 ◽  
Author(s):  
Il Doh ◽  
Il-Bum Kwon ◽  
Jiho Chang ◽  
Sejong Chun
Keyword(s):  
Wind Tunnel ◽  
Flow Velocity ◽  
Drag Force ◽  
Mass Flow ◽  
Surface Flow ◽  
Flow Sensor ◽  
Constant Current ◽  
Thermal Mass ◽  
Turbulent Drag ◽  
Mass Flow Sensor

Abstract A surface flow sensor is needed if turbulent drag force is to be measured over a vehicle, such as a car, a ship, and an airplane. In case of automobile industry, there are no automobile manufacturers which measure surface flow velocity over a car for wind tunnel testing. Instead, they rely on particle image velocimetry (PIV), pressure sensitive paint (PSP), laser Doppler anemometry (LDA), pitot tubes, and tufts to get information regarding the turbulent drag force. Surface flow sensors have not devised yet. This study aims at developing a surface flow sensor for measuring turbulent drag force over a rigid body in a wind tunnel. Two sensing schemes were designed for the fiber-optic distributed sensor and the thermal mass flow sensor. These concepts are introduced in this paper. As the first attempt, a thermal mass flow sensor has been fabricated. It was flush-mounted on the surface of a test section in the wind tunnel to measure the surface flow velocity. The thermal mass flow sensor was operated by either constant current or constant resistance modes. Resistance ratio was changed as the electric current was increased by the constant current mode, while power ratio was saturated as the resistance was increased by the constant resistance mode. Either the resistance ratio or the power ratio was changed with the flow velocity measured by a Pitot tube, located at the center of test section.

Design of a Large Scale Vertical Stabilizer Wind Tunnel Model for Active Flow Control Research

2012 ◽  
Author(s):  
Glenn Saunders ◽  
Edward Whalen ◽  
Helen Mooney ◽  
Sarah Zaremski
Keyword(s):  
Wind Tunnel ◽  
Flow Control ◽  
Large Scale ◽  
Active Flow Control ◽  
Scale Model ◽  
Tunnel Model ◽  
Control Research ◽  
Model Geometry ◽  
Design Requirements ◽  
Active Flow

The design, fabrication and installation of an approximately 1/6 scale model of an aircraft vertical stabilizer for research in Active Flow Control (AFC) is discussed. Highlighted are the unique design requirements of wind tunnel models, the specialized fabrication techniques employed to create them and the required close collaboration between industry, government and three academic institutions. The design of the model involves often competing constraints imposed by structural, instrumentation, aerodynamic, manufacturability and research-agenda considerations as well as cost and schedule. Instrumentation requires hundreds of pressure ports and six-axis force/torque sensing. Aerodynamic considerations necessitate high manufacturing precision, highly-skilled fabrication techniques and careful observance of model geometry throughout the design and fabrication processes. A scale model of a vertical stabilizer for AFC research was successfully designed, fabricated and deployed. The collaboratively designed model satisfies the structural, aerodynamic and research design constraints, and furthers the state of the art in Active Flow Control research.

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