Characterization of Unsteady Flow Structures Around Tandem Cylinders for Component Interaction Studies in Airframe Noise

Abstract

A joint computational and experimental study has been performed at NASA Langley Research Center to investigate the unsteady flow generated by the components of an aircraft landing gear system. Because the flow field surrounding a full landing gear is so complex, the study was conducted on a simplified geometry consisting of two cylinders in tandem arrangement to isolate and characterize the pertinent flow phenomena. This

Assessment of Hybrid RANS/LES Turbulence Models for Aeroacoustics Applications

“…5. The computational flow patterns seen in this figure are qualitatively similar to what has been observed in the experimental work of Jenkins et al 10 However, the reverse flow region based on SST-QL and HRLES results extend farther in the downstream direction compared to the measured data. This is not surprising, given that the flow separation occurs further upstream on the cylinder compared to the experimental value, and hence resulting in a wider and longer wake behind the cylinder.…”

“…Hutcheson et al 4 and Jenkins et al 3,10 have performed experimental studies for single and tandem cylinder configurations in the QFF and BART tunnels at NASA Langley Research Center. These experimental studies produced a large database consisting of steady surface pressures, detailed off surface measurements of the flow field using Particle Image Velocimetry (PIV), hot-wire measurements in the downstream wake, and unsteady pressure data.…”

Measurements of Unsteady Wake Interference Between Tandem Cylinders

“…Most studies of the unsteady flow field between tandem cylinders have used fluctuating surface pressure measurements and flow field spectra obtained using hot-wire anemometry to examine the effects of Reynolds number, freestream turbulence, surface roughness, and cylinder spacing on the flow structure associated with the different flow regimes described above. [8][9][10][11] Recent studies by Jenkins, et al 12 , Khorrami, et al 13 , and Henderson and Brooks 14 have added to this body of knowledge by providing additional insight into the unsteady near-field flow structure and its implications on noise radiation.…”

Simulations of Bluff Body Flow Interaction for Noise Source Modeling

“…In this section an overall view of the tandem cylinder flow field is provided by comparing the simulated results with the PIV measurements of Jenkins et al 19 . For L/D = 3.7, the predicted velocity field from the three grids considered is in remarkably close agreement with the experimental data.…”

“…The experiments were conducted in several phases in the Basic Aerodynamic Research Tunnel (BART) at NASA Langley Research Center (LaRC). Phase 1 of the experiment, discussed by Jenkins et al 19 , was targeted at providing steady surface pressures and detailed off-surface measurements of the flow field using Particle Image Velocimetry (PIV). In addition, hot-wire measurements in the wake of the rear cylinder were also conducted.…”