Flow visualization using momentum and energy transport tubes and applications to turbulent flow in wind farms

TL;DR

This paper introduces momentum and energy transport tubes as advanced flow visualization tools, demonstrating their application to turbulent wind farm flows and revealing how turbine spacing influences energy transport pathways.

Contribution

It generalizes classical stream-tubes to include momentum and energy fluxes, providing new insights into flow structures in wind farms through visualization of energy transport pathways.

Findings

Energy transport tubes vary significantly with turbine spacing.

Visualization reveals the paths of kinetic energy flux in wind farm flows.

Transport tubes help understand energy availability at turbines.

Abstract

As a generalization of the mass-flux based classical stream-tube, the concept of momentum and energy transport tubes is discussed as a flow visualization tool. These transport tubes have the property, respectively, that no fluxes of momentum or energy exist over their respective tube mantles. As an example application using data from large-eddy simulation, such tubes are visualized for the mean-flow structure of turbulent flow in large wind farms, in fully developed wind-turbine-array boundary layers. The three-dimensional organization of energy transport tubes changes considerably when turbine spacings are varied, enabling the visualization of the path taken by the kinetic energy flux that is ultimately available at any given turbine within the array.