Coupled Fluid-Structure Interaction Modelling of Loads Variation and Fatigue Life of a Full-Scale Tidal Turbine under the Effect of Velocity Profile

Abstract

Velocity profiles in tidal channels cause cyclic oscillations in hydrodynamic loads due to the dependence of relative velocity on angular position, which can lead to fatigue damage. Therefore, the effect of velocity profile on the load variation and fatigue life of large-scale tidal turbines is quantified here. This is accomplished using Fluid Structure Interaction (FSI) simulations created using the ANSYS Workbench software, which couples the fluid solver ANSYS CFX to the structural solver ANSYS transient structural. While these load oscillations only minimally impact power and thrust fluctuation for rotors, they can significantly impact the load variations on individual rotor blades. To evaluate these loadings, a tidal turbine within a channel with a representative flow that follows a 1/7th power velocity profile and an onset turbulence intensity of 5% is simulated. This velocity profile increases the thrust coefficient variation from mean cycle value of an individual blade from 2.8% to 9% and the variation in flap wise bending moment coefficient is increased from 4.9% to 19%. Similarly, the variation from the mean cycle value for blade deformation and stress of 2.5% and 2.8% increased to 9.8% and 10.3%, respectively. Due to the effect of velocity profile, the mean stress is decreased, whereas, the range and variation of stress are considerably increased.

Gyroscopic effect on a scaled rotor-bearing system

“…The simulation can use two eccentricity ratio assumptions. First, there is fix eccentricity (steady-state), such as the work presented by Wang et al (2019), Badshah et al (2019) and Liu et al (2010). Second, dependent eccentricity (transient state) that can be seen in the work presented by Lin et al (2018).…”

The Biomimetic Fin Performance Evaluation for an Efficient Autonomous Underwater Vehicle (Auv) to Support the Revolution in Military Affairs (Rma) in Underwater Defense

“…The present case of the biomimetic fin motion was considered as a strongly coupled category in which the alteration force by the fluid to the moving structure cannot be neglected. The motion of the biomimetic fin was set up in the Transient Structural system while the fluid analysis was performed in the CFX system (Afanasyeva & Lantsova, 2017;Badshah et al, 2019;Junaidin, 2017). The fin motion was an oscillating motion with a certain degree of amplitude.…”

Evaluating Mechanical Strength in Vertical-Axis Tidal Turbines: A Comparative Study of Internal Blade Structure and Material Selection through CFD Simulation

“…Another study investigated the impact of water depth and turbine rotational speed on the structural performance of horizontal stainless steel turbine blades (8). The effect of velocity profile on the load variation and fatigue life of large-scale steel horizontal tidal turbines are analyzed by (9), and influence of different tip speed ratio of Stainless steel HATT to the performance curve, pressure distribution on the blade, and velocity streamline was done by (10). A study on vertical-axis tidal turbines blade (11) investigates the relationship between the profile of the blade and the mechanical force generated, particularly.…”