Investigating wake characteristics of savonius turbine for off-grid wind energy: Analyzing operating influences

Shivam Singh Tomar and Anupam Dewan

Energy, 2025, vol. 316, issue C

Abstract: Savonius turbines are utilized on low-density open urban rooftops. Array of these rotors significantly increase energy production. Many studies on arrays employ two-dimensional Unsteady Reynolds-Averaged Navier-Stokes (URANS) approach to simulate flow. However, insufficient exploration exists in literature between studies of single rotor and of Savonius arrays, particularly in understanding wake of Savonius turbines. Thorough understanding of wake characteristics using three-dimensional computational fluid dynamics (CFD) is crucial for efficient setup of arrays. This study examines wake by adjusting operational conditions of Savonius rotor. For a tip speed ratio (TSR) 1.0, approximately 50 % and 75 % of streamwise velocity is recovered at downstream distances of 4 and 7 rotor diameters (D) from centroid. Two-dimensional simulations cannot capture the wake accurately, as significant entrainment on advancing side occurs from z-direction. Vortical structures, characterized by Q-criterion and z-vorticity, are smaller at higher TSRs due to increased interaction with returning blade side. Novel integral momentum approach determines optimal downstream turbine position without simulating downstream rotor. It segregates downstream region into nine areas and analyzes momentum flux to account for varied recovery rates across z-planes. Additionally, velocity profiles are estimated using hyperbolic secant function. Present findings provide critical insights for efficient arrangement of Savonius turbine arrays.

Keywords: Savonius vertical axis wind turbine; Wake; Tip speed ratio; Velocity profile; Savonius array; Momentum flux (search for similar items in EconPapers)
Date: 2025
References: Add references at CitEc
Citations:

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0360544225002051
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:316:y:2025:i:c:s0360544225002051

DOI: 10.1016/j.energy.2025.134563

Access Statistics for this article

Energy is currently edited by Henrik Lund and Mark J. Kaiser

More articles in Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().