scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Effect of vegetation on run-up and wall pressures due to cnoidal waves

TL;DR: In this article, the effect of vegetation on attenuating run-up over a plane slope of 1 : 30 due to the propagation of cnoidal waves was investigated. But the authors focused on the vertical wall fronted by two vegetation types, namely tandem and staggered vegetation.
Abstract: A comprehensive experimental investigation was carried out to understand the effect of vegetation in attenuating run-up over a plane slope of 1 : 30 due to the propagation of cnoidal waves. Two different types of vegetation configurations, namely tandem and staggered, are considered. Dynamic pressures exerted along a vertical wall fronted by these two vegetation types were measured, and the typical variation of dimensionless peak pressures for different relative depths of submergence of the pressure ports is reported as a function of dimensionless parameters involving the vegetation and wave characteristics. Further, typical results on the variation of the dimensionless peak run-up versus the surf similarity parameter only for the staggered configuration are also herein reported. Finally, the percentage reduction in wave run-up and pressures on the wall due to the presence of wall fronted by vegetation are reported.
Citations
More filters
Journal ArticleDOI
TL;DR: In this paper, the effects of long waves as simulated solitary waves on sediment transport to estimate the sediment transport rate in different coastal forest cover (CFC) densities were studied.

6 citations

Book ChapterDOI
01 Jan 2019
TL;DR: In this paper, an artificial, rigid, emerged vegetation for a length of 2 m is developed in a numerical wave tank of REEF3D. The model is tested for regular waves of height 0.08, 0.12, and 0.16 m and wave periods of 1.8 and 2 s in a water depth of 0.45 m.
Abstract: Coastal vegetation is a soft solution for protecting the coast from the action of waves by attenuating the wave height and reducing the energy of the waves. Effect of wave height attenuation as a result of the presence of emerged coastal vegetation is studied numerically by resolving the Reynolds-averaged Navier–Stokes (RANS) equations. A three-dimensional numerical wave tank model is simulated using an open source computational fluid dynamics (CFD) software REEF3D, and wave attenuation due to emerged coastal vegetation is determined. An artificial, rigid, emerged vegetation for a length of 2 m is developed in a numerical wave tank of REEF3D. The model is tested for regular waves of height 0.08, 0.12, and 0.16 m and wave periods of 1.8 and 2 s in a water depth of 0.40 and 0.45 m. The wave heights are measured at different locations along the vegetation meadow at 0.5 m intervals. The devolved numerical model is corroborated by comparing the obtained numerical results with the experimental results as reported by John et al. (Experimental investigation of wave attenuation through artificial vegetation meadow, ISH—HYDRO, [1]). The numerically obtained results are concurrent with the experimental results.

5 citations

Journal ArticleDOI
TL;DR: In this paper , the authors evaluated the efficacy of hard and soft countermeasures for tsunami impacts through a comprehensive literature review and compared the performance characteristics of countermeasures and related damaging processes by in-situ observations.
Abstract: Abstract Tsunamis pose a substantial threat to coastal communities around the globe. To counter their effects, several hard and soft mitigation measures are applied, the choice of which essentially depends on regional expectations, historical experiences and economic capabilities. These countermeasures encompass hard measures to physically prevent tsunami impacts such as different types of seawalls or offshore breakwaters, as well as soft measures such as long-term tsunami hazard assessment, tsunami education, evacuation plans, early-warning systems or coastal afforestation. Whist hard countermeasures generally aim at reducing the inundation level and distance, soft countermeasures focus mainly on enhanced resilience and decreased vulnerability or nature-based wave impact mitigation. In this paper, the efficacy of hard countermeasures is evaluated through a comprehensive literature review. The recent large-scale tsunami events facilitate the assessment of performance characteristics of countermeasures and related damaging processes by in-situ observations. An overview and comparison of such damages and dependencies are given and new approaches for mitigating tsunami impacts are presented.

4 citations

Journal ArticleDOI
TL;DR: In this article, the applicability of log law is analyzed above the vegetated canopy in a tilting flume with bed covered by artificial vegetation and arranged in a regular staggered configuration.
Abstract: Experimental investigation has been done to access turbulence characteristics just above the sparse flexible submerged vegetation zone in open-channel flow. The experimentation has been done in a tilting flume with bed covered by artificial vegetation and arranged in a regular staggered configuration. The applicability of log law is analysed above the vegetated canopy. Turbulent parameters such as velocity profiles, Reynolds stresses, turbulent intensities, quadrant analysis, turbulent production and diffusion, dissipation and stream power have been appraised to understand the hydrodynamics of vegetated channel. Results show that the log law is valid above the canopy of submerged vegetation with decreased Von-Karman constant. Maximum value of turbulent intensities and Reynolds stresses has been found above the canopy. Quadrant analysis shows that sweeps and ejections events are more dominating factors in submerged vegetated channel.

3 citations


Cites background from "Effect of vegetation on run-up and ..."

  • ...Sundar et al. (2011) have examined the effect of vegetation on run-up and wall pressures due to cnoidal waves....

    [...]

Journal ArticleDOI
TL;DR: In this paper, the authors present the results of an experimental study carried out with simulated rigid submerged and emergent vegetation meadows of varying plant densities in a wave flume 50m long, 0.71m wide and 1.1m deep.
Abstract: Coastal communities across the world are facing the need to adapt to rising sea levels, an increase in the frequency of natural hazards like storm surges, cyclones, tsunamis, and an increase in beach erosion. This present-day scenario calls for a sustainable, environment-friendly, and cost efficient solution for coastal protection. Under these circumstances, the role of vegetation in providing ecosystem services to coastal populations is becoming increasingly prominent. This work presents the results of an experimental study carried out with simulated rigid submerged and emergent vegetation meadows of varying plant densities in a wave flume 50 m long, 0.71 m wide and 1.1 m deep. The material used for modeling the vegetation is nylon. The tests are carried out with regular waves for water depths of 0.40 and 0.45 m, and wave periods 1.4–2 s at an interval of 0.2 s. Five different wave heights ranging from 0.08 to 0.16 m at an interval of 0.02 m are generated. Measurements of wave heights at differen...

3 citations


Cites background from "Effect of vegetation on run-up and ..."

  • ...Furthermore, these studies paved the way for detailed experimental investigations on the effect of vegetation in reducing the wave run up (Sundar et al. 2011) and the variation of forces on a model building placed at different distances from the vegetation belt subjected to the action of Cnoidal waves (Lakshmanan et al....

    [...]

  • ...Furthermore, these studies paved the way for detailed experimental investigations on the effect of vegetation in reducing the wave run up (Sundar et al. 2011) and the variation of forces on a model building placed at different distances from the vegetation belt subjected to the action of Cnoidal…...

    [...]

References
More filters
Journal ArticleDOI
TL;DR: In this article, an approximate theory is presented for non-breaking waves and an asymptotic result is derived for the maximum runup of solitary waves on plane beaches, and a series of laboratory experiments is described to support the theory.
Abstract: This is a study of the runup of solitary waves on plane beaches. An approximate theory is presented for non-breaking waves and an asymptotic result is derived for the maximum runup of solitary waves. A series of laboratory experiments is described to support the theory. It is shown that the linear theory predicts the maximum runup satisfactorily, and that the nonlinear theory describes the climb of solitary waves equally well. Different runup regimes are found to exist for the runup of breaking and non-breaking waves. A breaking criterion is derived for determining whether a solitary wave will break as it climbs up a sloping beach, and a different criterion is shown to apply for determining whether a wave will break during rundown. These results are used to explain some of the existing empirical runup relationships.

866 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the behavior of a wave as it climbs a sloping beach and obtained explicit solutions of the equations of the non-linear inviscid shallow-water theory for several physically interesting wave-forms.
Abstract: In this paper, we investigate the behaviour of a wave as it climbs a sloping beach. Explicit solutions of the equations of the non-linear inviscid shallow-water theory are obtained for several physically interesting wave-forms. In particular it is shown that waves can climb a sloping beach without breaking. Formulae for the motions of the instantaneous shoreline as well as the time histories of specific wave-forms are presented.

692 citations


"Effect of vegetation on run-up and ..." refers background in this paper

  • ...Carrier and Greenspan (1958) solved the shallow water equations analytically by obtaining solutions for the prediction of the long wave run-up over smooth plane beaches....

    [...]

Journal ArticleDOI
TL;DR: A study conducted after the 26th of December 2004 tsunami in 18 coastal hamlets along the south-east coast of India reiterates the importance of coastal mangrove vegetations and location characteristics of human inhabitation to protect lives and wealth from the fury of tsunami.
Abstract: A study conducted after the 26th of December 2004 tsunami in 18 coastal hamlets along the south-east coast of India reiterates the importance of coastal mangrove vegetations and location characteristics of human inhabitation to protect lives and wealth from the fury of tsunami. The tsunami caused human death and loss of wealth and these decreased with the area of coastal vegetation, distance and elevation of human inhabitation from the sea. Human inhabitation should be encouraged more than 1 km from the shoreline in elevated places, behind dense mangroves and or other coastal vegetation. Some plant species, suitable to grow in between human inhabitation and the sea for coastal protection, are suggested.

656 citations


"Effect of vegetation on run-up and ..." refers background in this paper

  • ...The dominant role of vegetation to reduce the inundation distance and run-up during the ingress of great Indian Ocean tsunami of 2004 is reported by Kathiresan and Rajendran (2005)....

    [...]

  • ...distance and run-up during the ingress of great Indian Ocean tsunami of 2004 is reported by Kathiresan and Rajendran (2005). The studies of Mascarenhas and Jayakumar (2008) indicate that large stretches of the coast of Tamil Nadu (South East...

    [...]

Book
01 Mar 1987
TL;DR: In this article, the authors describe wave mechanics and how to choose wave theories and design waves, and how this wave is used to obtain forces on a fixed offshore structure, if the structure is allowed to move, various methods of obtaining the motions of the structure are given.
Abstract: The subject of hydrodynamics applied to offshore structures is vast. The topics covered in this book aim to help the reader understand basic principles while at the same time giving the designer enough information for particular designs. Thus, results are given with derivations, and applications are discussed with the aid of examples, with an overview of the advantages and limitations of the method involved. This makes the book suitable as a text for undergraduate and graduate students specializing in offshore and ocean engineering. In addition, the final results, including tables and illustrations may be referenced directly without going through detailed derivations. They can therefore be used by design and applications engineers involved in offshore structure design. This title also introduces various types of offshore structures with reference to actual installations in various parts of the world. It describes wave mechanics and how to choose wave theories and design waves. After a choice of design wave is made, the author describes how this wave is used to obtain forces on a fixed offshore structure. If the structure is allowed to move, various methods of obtaining the motions of the structure are given. The short- and long-term responses are derived and different methods are described. The use of model tests to verify these methods at each step is shown.

632 citations


"Effect of vegetation on run-up and ..." refers methods in this paper

  • ...Considering the drag/inertia force regime (Chakrabarti 1983), the corresponding diameters for the exposed vegetal stems were determined....

    [...]

Journal ArticleDOI
TL;DR: A field study of the tidal currents, cohesive sediment dynamics and transport of organic carbon in a highly vegetated mangrove swamp was carried out at Middle Creek, Cairns, Australia as discussed by the authors.
Abstract: A field study of the tidal currents, cohesive sediment dynamics and transport of organic carbon in a highly vegetated mangrove swamp was carried out at Middle Creek, Cairns, Australia. The interaction of tidal currents and the vegetation generated jets, eddies and zones of stagnant waters which were numerically modelled. A high value of the Manning friction coefficient (n=0·1) was derived by the dense vegetation. About 80% of the suspended sediment brought in from coastal waters at spring flood tide was trapped in the mangroves, corresponding to about 10–12 kg of sediment m−1creek length/spring tide, resulting in a rise of the substrate by about 0·1 cm year−1. The selective trapping of clay was caused by flocculation of the finer particles in the mangroves. There was an indication of a slight inwelling of organic carbon. Creek water was readily differentiated from mangrove water by large differences in the molecular weight distribution of the dissolved organic carbon.

482 citations


"Effect of vegetation on run-up and ..." refers background in this paper

  • ...Through experimental studies, Furukawa et al. (1997) demonstrated that the wave dissipation depends on the forest density and the diameter of the tree trunks....

    [...]