Contributions Unsteady Pressure Distributions Due to Vortex-Induced Vibration of a Triangular Cylinder

1974 ◽  
pp. 433-442 ◽  
Author(s):  
C. F. M. Twigge-Molecey ◽  
W. D. Baines
Keyword(s):  
Vortex Induced Vibration ◽  
Unsteady Pressure ◽  
Pressure Distributions

Unsteady Pressure Measurement on Oscillating Blade in Transonic Flow Using Fast-Response Pressure-Sensitive Paint

2017 ◽  
Author(s):  
Toshinori Watanabe ◽  
Toshihiko Azuma ◽  
Seiji Uzawa ◽  
Takehiro Himeno ◽  
Chihiro Inoue
Keyword(s):  
Surface Pressure ◽  
Transonic Flow ◽  
Aerodynamic Force ◽  
Fast Response ◽  
Pressure Sensitive Paint ◽  
Unsteady Pressure ◽  
Pressure Distributions ◽  
Pressure Sensitive ◽  
Unsteady Surface Pressure ◽  
Response Pressure

A fast-response pressure-sensitive paint (PSP) technique was applied to the measurement of unsteady surface pressure of an oscillating cascade blade in a transonic flow. A linear cascade was used, and its central blade was oscillated in a translational manner. The unsteady pressure distributions of the oscillating blade and two stationary neighbors were measured using the fast-response PSP technique, and the unsteady aerodynamic force on the blade was obtained by integrating the data obtained on the pressures. The measurements made with the PSP technique were compared with those obtained by conventional methods for the purpose of validation. From the results, the PSP technique was revealed to be capable of measuring the unsteady surface pressure, which is used for flutter analysis in transonic conditions.

Further Developments in the Aerodynamic Analysis of Unsteady Supersonic Cascades—Part 1: The Unsteady Pressure Field

1977 ◽  
Vol 99 (4) ◽  
pp. 509-516 ◽  
Author(s):  
J. M. Verdon
Keyword(s):  
Velocity Potential ◽  
Pressure Field ◽  
Supersonic Stream ◽  
Axial Velocity Component ◽  
Unsteady Pressure ◽  
Pressure Distributions ◽  
Successive Solution ◽  
Construction Procedure ◽  
Present Procedure ◽  
Dependent Variables

This paper presents, in two parts, a theoretical investigation of the aerodynamic response produced by an oscillating cascade placed in a supersonic stream with subsonic axial velocity component. Predictions are based on the successive solution of two linear boundary value problems which treat the velocity potential and the pressure, respectively, as basic dependent variables. A solution for the potential has been reported earlier and is used here to provide upper surface blade pressure distributions. This information serves as a boundary condition for the second problem. The solution for the unsteady pressure field, described in Part 1, is obtained by a construction procedure which parallels that used earlier to determine the potential. With the present procedure, blade pressure difference distributions and aerodynamic coefficients are accurately and efficiently determined for both subresonant and superresonant blade motions. Supersonic resonance phenomena and selected numerical results are discussed in Part 2 of the paper.

Unsteady Pressure Measurement of an Axial Fan

2001 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Vortex Shedding ◽  
Pressure Measurement ◽  
Flow Characteristics ◽  
Rotational Frequency ◽  
Time Dependent ◽  
Pressure Measurements ◽  
Axial Fan ◽  
Unsteady Pressure ◽  
Pressure Distributions ◽  
Start Up

Abstract An unsteady pressure measurement system was developed to measure the unsteady pressure field of an axial fan. The fan unsteady pressure fields of an inlet and outlet were obtained at three axial positions for seven-radial directions. The results showed that there is a relatively long response time for pressure drop both in inlet and outlet sections during the fan start-up. The measurements also showed that, due to the vortex shedding from the trailing edge of each fan blade, the fan outlet unsteady pressure distributions have a primary frequency related to the fan operating frequency. The time-dependent pressure measurements showed that pressure distributions of inlet and outlet during the fan start-up were severely unsteady and the main variation frequency of the pressure is much smaller than the fan rotational frequency. The pressure measurement on the fan blades showed that the pressure oscillations were mainly dominated by the vortex shedding from the fen blades. A flow visualization study was also performed to validate the flow characteristics near the blade surface. A complete set of time-dependent pressure measurements along the blade fan surfaces, fan inlet and outlet are suitable for an axial fan database for an industrial use as well as CFD code validation.

Unsteady Pressure Measurement on Oscillating Blade in Transonic Flow Using Fast-Response Pressure-Sensitive Paint

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Toshinori Watanabe ◽  
Toshihiko Azuma ◽  
Seiji Uzawa ◽  
Takehiro Himeno ◽  
Chihiro Inoue
Keyword(s):  
Surface Pressure ◽  
Transonic Flow ◽  
Aerodynamic Force ◽  
Fast Response ◽  
Pressure Sensitive Paint ◽  
Unsteady Pressure ◽  
Pressure Distributions ◽  
Pressure Sensitive ◽  
Unsteady Surface Pressure ◽  
Response Pressure

A fast-response pressure-sensitive paint (PSP) technique was applied to the measurement of unsteady surface pressure of an oscillating cascade blade in a transonic flow. A linear cascade was used, and its central blade was oscillated in a translational manner. The unsteady pressure distributions of the oscillating blade and two stationary neighbors were measured using the fast-response PSP technique, and the unsteady aerodynamic force on the blade was obtained by integrating the data obtained on the pressures. The measurements made with the PSP technique were compared with those obtained by conventional methods for the purpose of validation. From the results, the PSP technique was revealed to be capable of measuring the unsteady surface pressure, which is used for flutter analysis in transonic conditions.

Effect of Clocking on the Unsteady Rotor Blade Loading in a 1.5-Stage Low-Speed Axial Compressor

2007 ◽  
Author(s):  
Huixia Jia ◽  
Konrad Vogeler
Keyword(s):  
Guide Vane ◽  
Pressure Fluctuations ◽  
Suction Side ◽  
Rotor Blades ◽  
Inlet Guide Vane ◽  
Mean Values ◽  
Design Point ◽  
Low Speed ◽  
Unsteady Pressure ◽  
Pressure Distributions

This paper presents the effect of clocking on the unsteady loading of the rotor blades in the first stage with an inlet guide vane row (IGV) of the Dresden Low-Speed Research Compressor (LSRC). The unsteady flow field of the Dresden LSRC at 10 IGV clocking positions for the design point was investigated using a 3D time-accurate viscous solver. The time-averaged pressure distributions on the pressure side (PS) and the suction side (SS) of the rotor blades at midspan (MS) are presented for different clocking positions. The effect of the clocking on the time-averaged Root Mean Square-value (RMS) of the unsteady pressure fluctuations of the rotor blades at MS is investigated. The unsteady pressure fluctuations on the PS and the SS of the rotor blades at MS for different clocking positions are presented and discussed. The unsteady blade pressure forces on the rotor blades, which are calculated from the profile pressure distributions, are presented and analysed for different clocking positions. The maximal fluctuation amplitude of the unsteady pressure forces on the rotor blades, which fluctuate around the nearly identical mean values for different clocking positions, can be reduced about 60 percent with the IGV clocking for the design point in the investigated configuration. The effect of the clocking on the time-resolved inlet- and outlet flow fields of the rotor blades is investigated and discussed.

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