Effects of inflow boundary layer on the wake of a radially non-uniform porous disk

Date

2021-05-01

Author

Abdulrahim, Anas
Akpolat, M. Tuğrul
Hassanein, Abdelrahman
Perçin, Mustafa
Uzol, Oğuz

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

382
views

0
downloads

This study presents the results of an experimental investigation focusing on the effects of the inflow boundary layer on the wake characteristics of a 0.12 m diameter porous disk with radially non-uniform porosity in terms of mean flow, turbulence, and wake scaling. Two-dimensional two-component particle image velocimetry measurements within the wake are performed up to 7.5 diameters downstream as the disk is lowered deeper into a boundary layer that is representative of a neutral atmospheric boundary layer over a flat terrain. Results show that otherwise symmetrical wake velocity profiles that exist outside the boundary layer get skewed and sheared around the disk centerline in the boundary layer due to the inflow wind shear. The turbulent kinetic energy, its production, and Reynolds shear stress levels in the wake get asymmetrical around the centerline of the disk such that the production of turbulent kinetic energy is observed to be higher above centerline. Due to the inflow shear, the wake centerline gets shifted downwards (i.e., toward the wind tunnel wall), which is in contrast to the observations on real wind turbine wakes in the literature where the wake actually lifts up. The asymmetrical and skewed velocity profiles both in the streamwise and cross-stream directions can be collapsed onto a single function by using proper wake scaling parameters based on the ratio of local strain to average strain within the velocity profile calculated separately for either side of the wake.

URI

https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85106417381&origin=inward
https://hdl.handle.net/11511/90839

Journal

Journal of Renewable and Sustainable Energy

DOI

https://doi.org/10.1063/5.0045404

Collections

Department of Aerospace Engineering, Article

Suggestions

OpenMETU
Core

EFFECTS OF INFLOW BOUNDARY LAYER ON THE WAKE CHARACTERISTICS OF A RADIALLY NON-UNIFORM POROUS DISC Abdulrahim, Anas; Uzol, Oğuz; Perçin, Mustafa; Department of Aerospace Engineering (2022-1-03) This thesis study presents the results of an experimental investigation focusing on the effects of inflow boundary layer on the wake characteristics of a porous disc (disc diameter-to-boundary layer height is 0.2) with radially non-uniform porosity in terms of mean flow, turbulence, wake scaling, and proper orthogonal decomposition. Two-dimensional two-component particle image velocimetry measurements within the wake are performed up to 7.5 diameters downstream as the disc is lowered deeper in to a boundary...
Effect of steady and transient wind shear on the wake structure and performance of a horizontal axis wind turbine rotor Sezer Uzol, Nilay; Uzol, Oğuz (2009-12-01) This paper presents an investigation of the effect of steady and transient freestream wind shear on the wake structure and performance characteristics of a horizontal axis wind turbine rotor. A new 3-D unsteady vortex-panel method potential flow solver based on a free-vortex-wake methodology, AeroSIM, is used for this purpose. The code is validated using the experimental data from the NREL UAE experiments, as well as checked against the theoretical models developed by previous researchers. Three-different i...
Effect of steady and transient wind shear on the wake structure and performance of a horizontal axis wind turbine rotor SEZER UZOL, NİLAY; Uzol, Oğuz (2013-01-01) This paper presents an investigation of the effect of steady and transient free-stream wind shear on the wake structure and performance characteristics of a horizontal axis wind turbine rotor. A new three-dimensional unsteady vortex-panel method potential flow solver based on a free-vortex wake methodology, AeroSIM+, is used for this purpose. The code is validated using the experimental data from the National Renewable Energy Laboratory Unsteady Aerodynamics Experiments. The effects of vortex core model, co...
Effect of thermal induced flexural strain cycles on the low cycle fatigue performance of integral bridge steel H-piles Karalar, Memduh; Dicleli, Murat (2016-10-01) Close examination of the field measurement data for integral bridges revealed that the measured cyclic flexural strains in steel H-piles at the abutments due to thermal fluctuations consist of large amplitude, primary small amplitude and secondary small amplitude cycles. The effect of the small amplitude strain cycles on the low cycle fatigue life of these steel H-piles has not been extensively studied yet. Accordingly, to investigate the effect of the small amplitude strain cycles on the low cycle fatigue ...
Effects of Substrate Parameters on the Resonance Frequency of Double-sided SRR Structures under Two Different Excitations Ekmekci, E.; Averitt, R. D.; Sayan, Gönül (2010-07-08) In this study, we numerically investigate the effects of substrate parameters (i.e., the thickness and the permittivity) on the resonance frequency of the double-sided SRR (DSRR) structure under two different excitation conditions. This includes either electric or magnetic excitations which are two common techniques to obtain a resonant effective permittivity or permeability, respectively. The numerical calculations are performed using CST Microwave Studio. The numerical results reveal a similar trend in th...

Citation Formats

A. Abdulrahim, M. T. Akpolat, A. Hassanein, M. Perçin, and O. Uzol, “Effects of inflow boundary layer on the wake of a radially non-uniform porous disk,” Journal of Renewable and Sustainable Energy, pp. 0–0, 2021, Accessed: 00, 2021. [Online]. Available: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85106417381&origin=inward.