Next Article in Journal
Hybrid Optimization Methodology (Exergy/Pinch) and Application on a Simple Process
Next Article in Special Issue
Wake Characteristics and Power Performance of a Drag-Driven in-Bank Vertical Axis Hydrokinetic Turbine
Previous Article in Journal
Changes in the Structure of Electricity Generation in Poland in View of the EU Climate Package
Previous Article in Special Issue
Experimental and Numerical Investigation of Wake Interactions of Marine Hydrokinetic Turbines
 
 
Article

On Blockage Effects for a Tidal Turbine in Free Surface Proximity

Department of Mechanical Engineering and Mechanics, Lehigh University, Bethlehem, PA 18015, USA
*
Author to whom correspondence should be addressed.
Energies 2019, 12(17), 3325; https://doi.org/10.3390/en12173325
Received: 7 August 2019 / Revised: 26 August 2019 / Accepted: 27 August 2019 / Published: 28 August 2019
(This article belongs to the Special Issue Fluid Dynamics in Marine and Hydrokinetic Energy System)
Experiments with a three-bladed, constant chord tidal turbine were undertaken to understand the influence of free surface proximity on blockage effects and near-wake flow field. The turbine was placed at various depths as rotational speeds were varied; thrust and torque data were acquired through a submerged sensor. Blockage effects were quantified in terms of changes in power coefficient and were found to be dependent on tip speed ratio and free surface to blade tip clearance. Flow acceleration near turbine rotation plane was attributed to blockage offered by the rotor, wake, and free surface deformation. In addition, particle image velocimetry was carried out in the turbine near-wake using time- and phase-averaged techniques to understand the mechanism responsible for the variation of power coefficient with rotational speed and free surface proximity. Slower wake propagation for higher rotational velocities and increased asymmetry in the wake with increasing free surface proximity was observed. Improved performance at high rotational speed was attributed to enhanced wake blockage, and performance enhancement with free surface proximity was due to the additional blockage effects caused by the free surface deformation. Proper orthogonal decomposition analysis revealed a downward moving wake for the turbine placed in near free surface proximity. View Full-Text
Keywords: tidal turbine; blockage; free surface; wake tidal turbine; blockage; free surface; wake
Show Figures

Figure 1

MDPI and ACS Style

Kolekar, N.; Vinod, A.; Banerjee, A. On Blockage Effects for a Tidal Turbine in Free Surface Proximity. Energies 2019, 12, 3325. https://doi.org/10.3390/en12173325

AMA Style

Kolekar N, Vinod A, Banerjee A. On Blockage Effects for a Tidal Turbine in Free Surface Proximity. Energies. 2019; 12(17):3325. https://doi.org/10.3390/en12173325

Chicago/Turabian Style

Kolekar, Nitin, Ashwin Vinod, and Arindam Banerjee. 2019. "On Blockage Effects for a Tidal Turbine in Free Surface Proximity" Energies 12, no. 17: 3325. https://doi.org/10.3390/en12173325

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop