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Anthony D. Lucey - One of the best experts on this subject based on the ideXlab platform.
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Flutter of spring-mounted flexible plates in uniform flow
Journal of Fluids and Structures, 2015Co-Authors: Richard Howell, Anthony D. LuceyAbstract:Abstract A fluid–structure interaction (FSI) system is studied wherein a cantilevered flexible plate aligned with a uniform flow has its upstream end attached to a spring mounting. This allows the entire system to oscillate in a direction perpendicular to that of the flow as a result of the mounting׳s dynamic interaction with the flow-induced oscillations, or flutter, of the flexible plate. We also study a hinged-free rotational-spring attachment as a comparison for the heaving system. This variation on classical plate flutter is motivated by its potential as an energy-harvesting system in which the reciprocating motion of the support system would be tapped for energy production. We formulate and deploy a hybrid of theoretical and computational modelling for the two systems and comprehensively map out their linear-stability characteristics at low mass ratio. Relative to a fixed cantilever, the introduction of the dynamic support in both systems yields lower flutter-onset flow speeds; this is desirable for energy-harvesting applications. We further study the effect of adding an Inlet Surface upstream of the mount as a means of changing the destabilising mechanism from single-mode flutter to modal-coalescence flutter which is a more powerful instability more suited to energy harvesting. This strategy is seen to be effective in the heaving system. However, divergence occurs in the rotational system for low spring natural frequencies and this would lead to its failure for energy production. Finally, we determine the power-output characteristics for both systems by introducing dashpot damping at the mount. The introduction of damping increases the critical speeds and its variation permits optimal values to be found that maximise the power output for each system. The addition of an Inlet Surface is then shown to increase significantly the power output of the heaving system whereas this design strategy is not equally beneficial for the rotational system.
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Energy Production Characteristics of a Spring-Mounted Cantilevered-Free Flexible Plate in a Uniform Flow
Volume 1: Symposia Parts A and B, 2012Co-Authors: Richard Howell, Anthony D. LuceyAbstract:We study a new fundamental system that comprises a cantilevered thin flexible plate exactly aligned with the direction of a uniform flow in which the upstream end of the flexible plate is not fixed. Instead, it is attached to a spring-damper system that allows the entire system to oscillate perpendicularly to the flow direction as a result of the mounting’s dynamic interaction with the flow-induced oscillations of the flexible plate. This models an energy-harvesting system whereby the rate of energy extraction by the damper represents power generation from the kinetic-energy flux of the mean flow transferred via fluttering motions of the flexible plate to the motion of the mounting system. The two-dimensional modelling presented is an extension of the methods in [1,2] that mixed numerical simulation with eigenvalue analysis to study a fixed cantilevered flexible plate. The present system also includes a rigid Inlet Surface upstream of and fixed to the spring-mounted cantilever. Ideal flow is assumed wherein the rotationality of the boundary-layers is modelled by vortex elements on the solid-fluid interface and the imposition of the Kutta condition at the plate’s trailing edge. The Euler-Bernoulli beam model is used for the structural dynamics. Results presented first show how the replacement of the fixed leading edge with an interactively oscillating mounting modify the well-known linear-stability characteristics of a fluttering plate. The overall effect is that the critical flow speed for flutter onset is reduced and this is desirable for the present energy-harvesting application. This entails some subtle but important changes to the destabilisation mechanisms. The power generating potential of the fluid-structure interaction system is then illustrated. The present model of the dynamics of the plate-support interaction has been simplified so as to demonstrate proof-of-concept; thus, a discussion of the way forward to a more complete model is presented to close the paper.Copyright © 2012 by ASME
Andrew Russ - One of the best experts on this subject based on the ideXlab platform.
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Removal, by Vegetated Biofilter, of Medium and Low Concentrations of Pollutants from Simulated Highway Runoff
Transportation Research Record, 2011Co-Authors: Gayle F Mitchell, R. Guy Riefler, Andrew RussAbstract:The removal of pollutants by a prototype of a vegetated biofilter was investigated at medium and low concentrations. The biofilter was 4 ft (1.2 m) wide by 14 ft (4.3 m) long and was tilted at slopes of 8:1, 4:1, and 2:1. Artificial runoff, formulated with metals, native soil, and oil at medium concentration, was delivered at a rate equivalent to a simulated 2-year storm event (medium flow) at each slope; an additional experiment using a 10-year storm event (high flow) was conducted at the 2:1 slope. The flow rates at the low concentration represented 10-year storm events. During each simulated storm event, samples were obtained from the Inlet, Surface runoff, and underdrain and analyzed for total and dissolved metals, total suspended solids (TSS), and oil and grease. Before and after all tests, specimens were extracted from the bed and analyzed for metal content in soil, roots, and grass. Results indicated that all constituents (seven total metals and TSS) were removed at levels above 75% (event mean con...
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Removal of Pollutants from Simulated Highway Runoff Using a Vegetated Biofilter
2010Co-Authors: Gayle F Mitchell, R. Guy Riefler, Andrew RussAbstract:Low impact development techniques can be integrated into stormwater management of linear transportation systems and afford opportunities to capitalize on the natural environment to mitigate stormwater. One of these techniques is the vegetated biofilter. A 4 ft (1.2 m) wide by 14 ft (4.3 m) long prototype vegetated biofilter was constructed on a moveable frame. Artificial runoff was delivered to the grass bed for four comprehensive tests at slopes and flow rates as follows: 8:1, medium; 4:1, medium; 2:1, medium; and 2:1, high. The medium and high flows represented storm runoff events typical in Ohio. Artificial runoff, formulated with metals and native soil, was applied to the bed at a “high” concentration for the first part of the event, followed by a “medium” concentration. During the simulation, samples were obtained from the Inlet, Surface runoff, and underdrain and analyzed for total and dissolved metals and TSS. Prior to and at the end of testing cores were extracted from the bed, separated into soil, roots and grass, and each component analyzed for metal content per mass of soil. Results indicated that all constituents (7 total metals and TSS) were removed at levels above 85% except for Ni in one test at 2:1 slope, high flow rate. Metals above background levels were found primarily in the first half (7 ft, 2.1 m) of the bed. Soil particles in the influent flow, tagged with La, were not resuspended and were not measured at any significant concentration in the outlet Surface flow.
Richard Howell - One of the best experts on this subject based on the ideXlab platform.
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Flutter of spring-mounted flexible plates in uniform flow
Journal of Fluids and Structures, 2015Co-Authors: Richard Howell, Anthony D. LuceyAbstract:Abstract A fluid–structure interaction (FSI) system is studied wherein a cantilevered flexible plate aligned with a uniform flow has its upstream end attached to a spring mounting. This allows the entire system to oscillate in a direction perpendicular to that of the flow as a result of the mounting׳s dynamic interaction with the flow-induced oscillations, or flutter, of the flexible plate. We also study a hinged-free rotational-spring attachment as a comparison for the heaving system. This variation on classical plate flutter is motivated by its potential as an energy-harvesting system in which the reciprocating motion of the support system would be tapped for energy production. We formulate and deploy a hybrid of theoretical and computational modelling for the two systems and comprehensively map out their linear-stability characteristics at low mass ratio. Relative to a fixed cantilever, the introduction of the dynamic support in both systems yields lower flutter-onset flow speeds; this is desirable for energy-harvesting applications. We further study the effect of adding an Inlet Surface upstream of the mount as a means of changing the destabilising mechanism from single-mode flutter to modal-coalescence flutter which is a more powerful instability more suited to energy harvesting. This strategy is seen to be effective in the heaving system. However, divergence occurs in the rotational system for low spring natural frequencies and this would lead to its failure for energy production. Finally, we determine the power-output characteristics for both systems by introducing dashpot damping at the mount. The introduction of damping increases the critical speeds and its variation permits optimal values to be found that maximise the power output for each system. The addition of an Inlet Surface is then shown to increase significantly the power output of the heaving system whereas this design strategy is not equally beneficial for the rotational system.
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Energy Production Characteristics of a Spring-Mounted Cantilevered-Free Flexible Plate in a Uniform Flow
Volume 1: Symposia Parts A and B, 2012Co-Authors: Richard Howell, Anthony D. LuceyAbstract:We study a new fundamental system that comprises a cantilevered thin flexible plate exactly aligned with the direction of a uniform flow in which the upstream end of the flexible plate is not fixed. Instead, it is attached to a spring-damper system that allows the entire system to oscillate perpendicularly to the flow direction as a result of the mounting’s dynamic interaction with the flow-induced oscillations of the flexible plate. This models an energy-harvesting system whereby the rate of energy extraction by the damper represents power generation from the kinetic-energy flux of the mean flow transferred via fluttering motions of the flexible plate to the motion of the mounting system. The two-dimensional modelling presented is an extension of the methods in [1,2] that mixed numerical simulation with eigenvalue analysis to study a fixed cantilevered flexible plate. The present system also includes a rigid Inlet Surface upstream of and fixed to the spring-mounted cantilever. Ideal flow is assumed wherein the rotationality of the boundary-layers is modelled by vortex elements on the solid-fluid interface and the imposition of the Kutta condition at the plate’s trailing edge. The Euler-Bernoulli beam model is used for the structural dynamics. Results presented first show how the replacement of the fixed leading edge with an interactively oscillating mounting modify the well-known linear-stability characteristics of a fluttering plate. The overall effect is that the critical flow speed for flutter onset is reduced and this is desirable for the present energy-harvesting application. This entails some subtle but important changes to the destabilisation mechanisms. The power generating potential of the fluid-structure interaction system is then illustrated. The present model of the dynamics of the plate-support interaction has been simplified so as to demonstrate proof-of-concept; thus, a discussion of the way forward to a more complete model is presented to close the paper.Copyright © 2012 by ASME
Gayle F Mitchell - One of the best experts on this subject based on the ideXlab platform.
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Removal, by Vegetated Biofilter, of Medium and Low Concentrations of Pollutants from Simulated Highway Runoff
Transportation Research Record, 2011Co-Authors: Gayle F Mitchell, R. Guy Riefler, Andrew RussAbstract:The removal of pollutants by a prototype of a vegetated biofilter was investigated at medium and low concentrations. The biofilter was 4 ft (1.2 m) wide by 14 ft (4.3 m) long and was tilted at slopes of 8:1, 4:1, and 2:1. Artificial runoff, formulated with metals, native soil, and oil at medium concentration, was delivered at a rate equivalent to a simulated 2-year storm event (medium flow) at each slope; an additional experiment using a 10-year storm event (high flow) was conducted at the 2:1 slope. The flow rates at the low concentration represented 10-year storm events. During each simulated storm event, samples were obtained from the Inlet, Surface runoff, and underdrain and analyzed for total and dissolved metals, total suspended solids (TSS), and oil and grease. Before and after all tests, specimens were extracted from the bed and analyzed for metal content in soil, roots, and grass. Results indicated that all constituents (seven total metals and TSS) were removed at levels above 75% (event mean con...
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Removal of Pollutants from Simulated Highway Runoff Using a Vegetated Biofilter
2010Co-Authors: Gayle F Mitchell, R. Guy Riefler, Andrew RussAbstract:Low impact development techniques can be integrated into stormwater management of linear transportation systems and afford opportunities to capitalize on the natural environment to mitigate stormwater. One of these techniques is the vegetated biofilter. A 4 ft (1.2 m) wide by 14 ft (4.3 m) long prototype vegetated biofilter was constructed on a moveable frame. Artificial runoff was delivered to the grass bed for four comprehensive tests at slopes and flow rates as follows: 8:1, medium; 4:1, medium; 2:1, medium; and 2:1, high. The medium and high flows represented storm runoff events typical in Ohio. Artificial runoff, formulated with metals and native soil, was applied to the bed at a “high” concentration for the first part of the event, followed by a “medium” concentration. During the simulation, samples were obtained from the Inlet, Surface runoff, and underdrain and analyzed for total and dissolved metals and TSS. Prior to and at the end of testing cores were extracted from the bed, separated into soil, roots and grass, and each component analyzed for metal content per mass of soil. Results indicated that all constituents (7 total metals and TSS) were removed at levels above 85% except for Ni in one test at 2:1 slope, high flow rate. Metals above background levels were found primarily in the first half (7 ft, 2.1 m) of the bed. Soil particles in the influent flow, tagged with La, were not resuspended and were not measured at any significant concentration in the outlet Surface flow.
R. Guy Riefler - One of the best experts on this subject based on the ideXlab platform.
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Removal, by Vegetated Biofilter, of Medium and Low Concentrations of Pollutants from Simulated Highway Runoff
Transportation Research Record, 2011Co-Authors: Gayle F Mitchell, R. Guy Riefler, Andrew RussAbstract:The removal of pollutants by a prototype of a vegetated biofilter was investigated at medium and low concentrations. The biofilter was 4 ft (1.2 m) wide by 14 ft (4.3 m) long and was tilted at slopes of 8:1, 4:1, and 2:1. Artificial runoff, formulated with metals, native soil, and oil at medium concentration, was delivered at a rate equivalent to a simulated 2-year storm event (medium flow) at each slope; an additional experiment using a 10-year storm event (high flow) was conducted at the 2:1 slope. The flow rates at the low concentration represented 10-year storm events. During each simulated storm event, samples were obtained from the Inlet, Surface runoff, and underdrain and analyzed for total and dissolved metals, total suspended solids (TSS), and oil and grease. Before and after all tests, specimens were extracted from the bed and analyzed for metal content in soil, roots, and grass. Results indicated that all constituents (seven total metals and TSS) were removed at levels above 75% (event mean con...
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Removal of Pollutants from Simulated Highway Runoff Using a Vegetated Biofilter
2010Co-Authors: Gayle F Mitchell, R. Guy Riefler, Andrew RussAbstract:Low impact development techniques can be integrated into stormwater management of linear transportation systems and afford opportunities to capitalize on the natural environment to mitigate stormwater. One of these techniques is the vegetated biofilter. A 4 ft (1.2 m) wide by 14 ft (4.3 m) long prototype vegetated biofilter was constructed on a moveable frame. Artificial runoff was delivered to the grass bed for four comprehensive tests at slopes and flow rates as follows: 8:1, medium; 4:1, medium; 2:1, medium; and 2:1, high. The medium and high flows represented storm runoff events typical in Ohio. Artificial runoff, formulated with metals and native soil, was applied to the bed at a “high” concentration for the first part of the event, followed by a “medium” concentration. During the simulation, samples were obtained from the Inlet, Surface runoff, and underdrain and analyzed for total and dissolved metals and TSS. Prior to and at the end of testing cores were extracted from the bed, separated into soil, roots and grass, and each component analyzed for metal content per mass of soil. Results indicated that all constituents (7 total metals and TSS) were removed at levels above 85% except for Ni in one test at 2:1 slope, high flow rate. Metals above background levels were found primarily in the first half (7 ft, 2.1 m) of the bed. Soil particles in the influent flow, tagged with La, were not resuspended and were not measured at any significant concentration in the outlet Surface flow.