Year: 2012 Language: english Author: G. M. Dadd Genre: Research papers Publisher: University of Southampton Format: PDF Quality: eBook Pages count: 215 Description: Kite propulsion has emerged as an attractive means to harness wind power in a way that yields environmental and financial benefits. An understanding of the dynamics that affect kite motion and the resulting forces is required to facilitate the design and optimization of kite propulsion systems. In this thesis results from two line tension models are compared with experimentally recorded time histories for dynamic kite flight. New methodologies for investigating kite performance are established. The first zero mass model assumes that the kite and lines are weightless. The second, lumped mass model, considers the kites mass and thus makes use of the equations of motion. It is found that the two different models converge to the same result in the limit where the kite mass tends to zero. The zero mass model has been shown to compare favourably with experimental results. A method for parameterising figure of eight shape kite trajectories and for predicting kite velocity is presented. Results are shown for a variety of manoeuvre shapes, assuming realistic performance characteristics from an experimental test kite. Using a 320m 2 kite, with 300m long flying lines in 6.18ms −1 wind, a time averaged propulsive force of 16.7 tons is achievable. A typical kite force polar is presented and a new sensitivity study is carried out to identify the importance of various parameters in the system. Small horizontally orientated figure of eights shape kite trajectories centred on an elevation of 15 ◦ are preferred for maximising propulsive benefit. Force is found to be highly sensitive to aspect ratio. Increasing aspect ratio from 4 to 5 is estimated to yield up to 15% more drive force.
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Kite Dynamics for Ship Propulsion
Year: 2012
Language: english
Author: G. M. Dadd
Genre: Research papers
Publisher: University of Southampton
Format: PDF
Quality: eBook
Pages count: 215
Description: Kite propulsion has emerged as an attractive means to harness wind power in a way that yields environmental and financial benefits. An understanding of the dynamics that affect kite motion and the resulting forces is required to facilitate the design and optimization of kite propulsion systems.
In this thesis results from two line tension models are compared with experimentally recorded time histories for dynamic kite flight. New methodologies for investigating kite performance are established. The first zero mass model assumes that the kite and lines are weightless.
The second, lumped mass model, considers the kites mass and thus makes use of the equations of motion. It is found that the two
different models converge to the same result in the limit where the kite mass tends to zero. The zero mass model has been shown to compare favourably with experimental results. A method for parameterising figure of eight shape kite trajectories and for predicting kite velocity is presented. Results are shown for a variety of manoeuvre shapes, assuming realistic performance characteristics from an experimental test kite. Using a 320m 2 kite, with 300m long flying lines in 6.18ms −1 wind, a time averaged propulsive force of 16.7 tons is achievable. A typical kite force polar is presented and a new sensitivity study is carried out to identify the importance of various parameters in the system. Small horizontally orientated figure of eights shape kite trajectories centred on an elevation of 15 ◦ are preferred for maximising propulsive benefit.
Force is found to be highly sensitive to aspect ratio. Increasing aspect ratio from 4 to 5 is estimated to yield up to 15% more drive force.