A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Periodic water waves through suspended canopy
Abstract Small-amplitude water waves passing through a suspended canopy is studied. The area of suspended canopy is modeled by an array of vertical rigid cylinders with periodic spacing. Assuming that the diameter of cylinders and their spacing are much smaller than the typical incident wavelength, the homogenization theory (method of multiple-scale perturbation) is applied to create coupled micro-scale (cylinder spacing) and macro-scale (wavelength) problems. The micro-scale problem describes turbulent flows within a unit cell of the cylinder array, being driven by the macro-scale pressure gradients. Employing the concept of averaged energy balance over a wave period, the micro-scale flows determine the eddy viscosity, which damps the waves in the macro-scale flows. Eigenfunction expansions method is used to solve the macro-scale problem, in which a complex frequency dispersion relation is solved numerically by a multiple successive approximation technique. The potential decomposition method, which can avoid solving a complex frequency dispersion relation, is also employed to validate the accuracy of the eigenfunction expansions method. Both methods yield accurate solutions. However, the eigenfunction expansions method is relatively straightforward and can unify the solutions for suspended canopy and emergent vegetation. A new set of flume experiments of waves through suspended canopy is conducted and experimental data are used to check present solutions. Very good agreement has been observed. Finally, the effectiveness of suspended canopy, submerged and emergent vegetation on wave attenuation is discussed.
Highlights A semi-analytical solution to water waves scattering by suspended canopy is presented. The eigenfunction expansions method is used to solve the macro (wavelength)-scale problem analytically, in which a multiple successive approximation method is employed to find the eigenvalues from the complex frequency dispersion relation. A new set of flume experiments has been conducted to verify the present model results. From the model and experiment comparison test, it is shown that the present theory performs well as long as the assumptions of the theory are satisfied. The present model unifies the suspended canopy and emergent forest problem. The effectiveness of suspended canopy, submerged and emergent vegetation on wave attenuation is also discussed.
Periodic water waves through suspended canopy
Abstract Small-amplitude water waves passing through a suspended canopy is studied. The area of suspended canopy is modeled by an array of vertical rigid cylinders with periodic spacing. Assuming that the diameter of cylinders and their spacing are much smaller than the typical incident wavelength, the homogenization theory (method of multiple-scale perturbation) is applied to create coupled micro-scale (cylinder spacing) and macro-scale (wavelength) problems. The micro-scale problem describes turbulent flows within a unit cell of the cylinder array, being driven by the macro-scale pressure gradients. Employing the concept of averaged energy balance over a wave period, the micro-scale flows determine the eddy viscosity, which damps the waves in the macro-scale flows. Eigenfunction expansions method is used to solve the macro-scale problem, in which a complex frequency dispersion relation is solved numerically by a multiple successive approximation technique. The potential decomposition method, which can avoid solving a complex frequency dispersion relation, is also employed to validate the accuracy of the eigenfunction expansions method. Both methods yield accurate solutions. However, the eigenfunction expansions method is relatively straightforward and can unify the solutions for suspended canopy and emergent vegetation. A new set of flume experiments of waves through suspended canopy is conducted and experimental data are used to check present solutions. Very good agreement has been observed. Finally, the effectiveness of suspended canopy, submerged and emergent vegetation on wave attenuation is discussed.
Highlights A semi-analytical solution to water waves scattering by suspended canopy is presented. The eigenfunction expansions method is used to solve the macro (wavelength)-scale problem analytically, in which a multiple successive approximation method is employed to find the eigenvalues from the complex frequency dispersion relation. A new set of flume experiments has been conducted to verify the present model results. From the model and experiment comparison test, it is shown that the present theory performs well as long as the assumptions of the theory are satisfied. The present model unifies the suspended canopy and emergent forest problem. The effectiveness of suspended canopy, submerged and emergent vegetation on wave attenuation is also discussed.
Periodic water waves through suspended canopy
Hu, Jie (author) / Tang, Xiaochun (author) / Lin, Pengzhi (author) / Liu, Philip L-F. (author)
Coastal Engineering ; 163
2020-10-24
Article (Journal)
Electronic Resource
English