... gauge integrity is shown in the large RMS amplitudes at reduced velocities below 50. The uncertainty here is recognized in the range of reduced velocities taken for the stability threshold, 50–75. flow instability heat exchangers pipe flow pipes turbulence vibrations vortices wear...

... of the acoustic particle velocity for the onset of acoustic resonance in steam generator and tubular heat exchanger tube banks. 20 10 2009 16 06 2010 30 07 2010 30 07 2010 acoustic resonance boilers heat exchangers pipe flow pipes vortices In previous studies ( 1 2...

.... For the first condition, which occurred at low flow velocities where the natural vortex shedding frequency was below the acoustic resonance frequency, fully developed vortices formed in both the gap region between the cylinders and in the wake. These vortices were found to be in phase with each other...

... in a springlike manner with no inertia. The mechanism of vortex shedding across a cavity has been investigated in many circumstances. The phenomenon is nonlinear and involves the rolling up of the shear layer to produce vortices. For small amplitudes the shear layer oscillations add energy to the system...

... turbulence vortices wakes Noise generated by aircraft during take-off and landing is becoming an ever increasing problem due to stricter noise regulations. Recent success in aero-engine noise reduction has led to an increased interest in the noise generated by the aircraft undercarriage, where much...

... simulation flow visualisation shapes (structures) vortices wakes Phase relationship between the cross-flow oscillation and the lift coefficient on the cylinder: (solid line) cross-flow oscillation in m/s, and (◆) lift force coefficient To account for the effect of the resonant sound...

.... 0022-1120 10.1017/S0022112085002890 , 161 , pp. 217 – 237 . Ziada , S. , and Oengoeren , A. , 1992 , “ Vorticity Shedding and Acoustic Resonance in an In-Line Tube Bundle, Part I: Vorticity Shedding ,” J. Fluids Struct. 0889-9746 , 6 , pp. 271 – 292 . Ziada , S...

... is investigated experimentally. As a result, the following phenomena are clarified. Three types of flow patterns were observed: flow pattern A, with unsteady vortices, flow pattern B, with a single swirl and a vortex, and flow pattern C, with twin swirls. The flow pattern changes from A to B or C as the amplitude...

... force, Eq. 7 , is also indicated. When Reynolds number is below 33,000, a small peak appears at not only the nondimensional frequency 0.3 but also at 0.6, which is twice the vortex shedding frequency. It is assumed that a pair of vortices can excite the structure once in the lift direction and twice...

... ⩽ Re ⩽ 8.2 × 10 5 as shown in Fig. 13 . The lock-in vibration in the drag direction due to Karman vortex shedding began at Vr = 1.1 . The lock-in vibration in the lift direction due to Karman vortices began at Vr = 2.3 . The lift direction lock-in vibration continued...

...; revised manuscript received July 16, 2001. Associate Editor: M. J. Pettigrew. 22 July 2001 18 March 2001 16 July 2001 vortices fluid dynamics nonlinear systems The foregoing models were developed with the goal of predicting the lock-in response due to vortex excitation...

...; revised manuscript received July 10, 2001. Associate Editor: M. J. Pettigrew. 22 July 2001 29 March 2001 10 July 2001 heat exchangers vibrations fluid dynamics flow instability vortices There has been an increased effort in recent years to improve the heat transfer...

... June 19, 2001. Associate Editor: Y. W. Kwon. 14 March 2001 19 June 2001 vortices aerodynamics harmonics wakes Several years ago, the higher-harmonic-control aero-acoustic rotor test (HART) program was conducted at the German-Dutch wind tunnel (DNW) as a cooperative...