On integrating object detection capability into a coastal energy conversion system
Abstract
Near-shore wave energy converter arrays may be designed to provide uninterrupted power to a number of coastal sensing applications, including sensors monitoring meteorological conditions, sea-water chemical/physical properties, tsunamis and storm surges, fish and other marine life, coastal and sea-floor conditions, etc. Active control seeking near-optimum hydrodynamic operation has been shown to enable a dramatic reduction in device size for required amounts of power. Certain features of the control strategies that we have been developing make them particularly amenable to incorporation of additional sensing capability based on the wave patterns generated by intruding submerged objects (at distances on the order of 1000 m), in particular, the phase changes to the approaching wave field that occur in the presence of an object.We propose to investigate schemes for actively controlled wave energy converter arrays in coastal waters which enable detection of intruding marine vessels by monitoring the spatial and temporal energy conversion rates over the arrays. The proposed approach mainly utilizes a linear-theory based understanding of wave propagation, body hydrodynamics, and controller design, but also incorporates nonlinear extensions based on Volterra series modeling. We are interested in using small device sizes, for which response nonlinearities can be significant.Therefore, we propose to exploit the nonlinearities to enhance energy generation. Furthermore, we also propose to investigate ways to utilize features of the nonlinear response that enable preferential coupling to certain phase signatures, so that energy conversion by certain array elements would imply the presence of an object. Analysis and simulation results on arrays of moored devices will be extended to free-floating arrays.The first objective of the overall effort is to evaluate our proposed techniques through analysis and simulation. For near-shore sea areas to be identified, two categories or types of array designs with their own particular control strategies will be investigated, using Hydrodynamics and Controls based analytical techniques and detailed simulations (linear and nonlinear).Necessary in this process will be the characterization of the phase-change signatures of various submerged objects when stationary and when in translation. This knowledge will provide the test parameters for the designs to be investigated. The first two years of the overall, 4-yearlong, effort we envision are expected to provide the groundwork for the development of a prototype system. Prior to `at-sea prototype testing, we propose first to test the prototype in awave-basin environment. To provide reliable designs for the testing in the wave basin, wave tank testing under simplified conditions is also proposed. The proposed year-by-year objectives and costs are listed in the following sections. The overall testing sequence from wave tank tests through wave-basin tests to `at sea tests is expected to occur over years 3 and 4, which are indicated below as options 1 and 2 respectively. Michigan Technological University (MTU) will provide technical leadership and support throughout the project.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- May 05, 2017
- Source ID
- N000141712273
Entities
People
- Umesh A. Korde
Organizations
- Michigan Technological University
- Office of Naval Research
- United States Navy