Unsteady wall pressure characteristics of a 90 degree elbow in high Reynolds numbers

Iwamoto, Yukiharu; Yamano, Hidemasa

doi:10.1299/jfst.2014jfst0055

Cited by 5 publications

(2 citation statements)

References 10 publications

(12 reference statements)

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“…For flow-induced vibration, the studies on the acoustic loading on a plate behind a backward facing step (Nilsson, et al, 2013) and the unsteady wall pressure characteristics of a 90 degree elbow (Iwamoto and Yamano, 2013) are presented. As a fundamental study for vibration-power generators, the free-vibration tests of cantilevered rectangular prisms are carried out, and the effects of the prism shape and the free-stream turbulence on the vibration characteristics are investigated .…”

Section: Aeroacoustic Noise and Flow-induced Vibrationmentioning

confidence: 99%

Recent advancements toward the understanding and control of turbulent flows (Summary of ICJWSF2013)

Toyoda

Hiramoto

2014

JFST

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The 4 th International Conference on Jets, Wakes and Separated Flows (ICJWSF2013) was held in Nagoya, Japan, in September 2013. Advanced papers were presented at the conference, contributing to the progress of the research. This report is a summary of the published papers, focusing on turbulent flows. The papers are classified to seven fields: generation of turbulence fields, free shear flows, separated flows, wall shear flows, multi-physics flows, fluid machinery, and numerical methods/bio-fluid mechanics. The research works in each field are reviewed, noting the contribution to the understanding and control of turbulent flows. For generation of turbulent fields, the unique features of fractal-grid turbulence are discussed by the results of DNS and experiments. For free shear flows, the fundamental features are investigated, and various flow-control methods are demonstrated in engineering applications. For separated flows, many studies on separation control are presented, especially demonstrating the effectiveness of plasma actuators. For wall shear flows, the latest works are presented, revisiting the characteristics of statics and turbulent structures by the recent results of DNS and experiments. For multi-physics flows, the studies for engineering applications are presented in the fields of multiphase flows, reacting flows related to combustion, and aeroacoustics. The results suggest useful ideas to develop innovative technologies in each field. For fluid machinery, interesting studies of wind turbines are presented to increase efficiency. In conclusions, the contribution of the conference is summarized and the future issues on the research of turbulent flows are mentioned.

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Section: Aeroacoustic Noise and Flow-induced Vibrationmentioning

confidence: 99%

Recent advancements toward the understanding and control of turbulent flows (Summary of ICJWSF2013)

Toyoda

Hiramoto

2014

JFST

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“…1. There have been several investigations on the flow inside and downstream of a 90 • bend, ranging from CFD [18][19][20][21][22][23][24][25] to experimental studies [26][27][28][29][30]. Most of the investigations mainly focus on the flow inside or in the vicinity of the bend.…”

Section: Introductionmentioning

confidence: 99%

Hybrid LES/RANS simulations of a 90° pipe bend using different CFD solvers

Ekat,

Weissenbrunner,

Straka

et al. 2023

OpenFOAM J

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In this study, the performance of several RANS and hybrid LES/RANS turbulence models along with different CFD solvers (ANSYS Fluent, OpenFOAM and RapidCFD) is tested in terms of their ability to reproduce the flow downstream of a 90° pipe bend. The focus is on the temporal mean profiles downstream of the bend up to approximately 31 times the pipe's diameter D. The turbulence models' accuracy is evaluated by means of performance indicators and flow profiles in comparison to LDA measurements. The results demonstrate that the use of RANS models is suitable as long as the location of interest is in the vicinity of the bend up to approximately 10 D downstream of the bend. With increasing distance, the accuracy of the RANS models decreases, and the use of hybrid LES/RANS models is recommended.Three hybrid LES/RANS models are tested: the stress-blended eddy simulation (SBES) model as well as the Spalart-Allmaras-based and the k-omega SST-based improved delayed detached eddy simulation (IDDES) models. All three models show enhanced results for a distance to the bend >10 D. Additionally, it is found that in this geometry configuration, the IDDES models require a transient inlet. The flow separation due to the redirection inside the bend is too weak to generate turbulent fluctuations and a fast transition to full LES mode in the separation region. Due to the turbulent excitation at the inlet, the RANS region downstream of the bend is distinctly reduced, resulting in an enhanced performance of the hybrid IDDES models.

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