HYDRAULICS. ENGINEERING HYDROLOGY. HYDRAULIC ENGINEERING

Scour study in front of the breakwater caused by the oblique waves ifluence

Vestnik MGSU 2/2014
  • Sharova Vera Vladimirovna - Moscow State University of Civil Engineering (National Research University) (MGSU) postgraduate student, Department of Hydraulic Engineering, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe Shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 179-186

This paper presents a study of the scour in front of the breakwater caused by oblique waves influence. The experiments were conducted to investigate this scour. The experimental results indicate that the maximum depth of scour hole is observed near the breakwater. The scour depth increases as a wave period and incident wave angleincrease. While comparing the present experimental results with the previous study, it is found out that the scour caused by oblique waves influence considerably differs from the scour caused by the influence of straight waves. Breakwater is an important component of a sea port. It is intended to protect the port water area from the impacts of waves, currents and sediments. The scour in front of the breakwater may occur as a result of waves and currents. It may cause the damage of a construction and stop the proper functioning of the port. Therefore the study of scour is an important task of hydraulic construction.When oblique waves approach the breakwater the system of three-dimensional waves are formed, which are called “short-crested waves”. These waves generate a current along the breakwater front. The current interacts with the ground and causes erosion of the bed. This mechanism differs from the mechanism of erosion in the case of frontal approach of waves when the standing waves are formed. Namely, erosion of the bed is the result of the wave velocity increase due to the reflection of waves at the structure. However, in engineering practice of hydraulic structures design, the influence of oblique waves is neglected and is taken into account only in case of the regular incoming of the waves.

DOI: 10.22227/1997-0935.2014.2.179-186

References
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  2. Belyaev N.D. Zashchita osnovaniy ledostoykikh platform ot razmyva [The Protection of Ice-resistant Platforms Foundations from Scour]. Predotvrashchenie avariy zdaniy i sooruzheniy [Accident Prevention of Buildings and Structures]. 2009. Available at: http://www.pamag.ru/pressa/razmiv.
  3. Herbich J.B., Bretschneider C.L. Short-crested Waves. Handbook of Coastal and Ocean Engineering. 1990.
  4. Hsu J.R.C., Tsuchiya Y., Silvester R. Boundary-layer Velocities and Mass Transport in Short-crested Waves. Journal of Fluid Mechanics. 1980, vol. 99, no. 2, pp. 321—342. DOI: http://dx.doi.org/10.1017/S0022112080000638.
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  6. Khalfin I.Sh. Vozdeystvie voln na morskie neftegazopromyslovye sooruzheniya [The Impact of Waves on the Offshore Oil and Gas Structures]. Moscow, 1990, 310 p.
  7. Khalfin I.Sh. O prognoze glubiny mestnogo razmyva dna u tsilindricheskikh opor bol'shogo diametra pri techenii i volnenii [On the Prediction of Local Scour Depth at the Bottom of Cylindrical Supports with Large Diameter in Case of Flow and Heave]. Tekhnika i tekhnologiya dlya osvoeniya resursov nefti i gaza na kontinental'nom shel'fe : sbornik nauchnykh trudov [Technologies for Oil and Gas Resources Development on the Continental Shelf]. Riga. VNIImor-geo Publ., 1983, pp. 16—27.
  8. Summer B.M., Christiansen N., Fredsoe J. Influence of Cross Section on Wave Scour around Piles. Journal of Waterway, Port, Coastal and Ocean Engineering. 1993, vol. 119, no. 5, pp. 477—495. DOI: http://dx.doi.org/10.1061/(ASCE)0733-950X(1993)119:5(477)).
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INFLUENCE OF SEDIMENT SIZE ON LOCAL SCOUR DUE TO OBLIQUE WAVES NEAR BREAKWATER

Vestnik MGSU 9/2016
  • Sharova Vera Vladimirovna - Moscow State University of Civil Engineering (National Research University) (MGSU) postgraduate student, Department of Hydraulic Engineering, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe Shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Kantarzhi Igor’ Grigor’evich - Moscow State University of Civil Engineering (National Research University) (MGSU) Doctor of Technical Sciences, Professor, acting chair, Department of Hydraulic Engineering, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe Shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 108-118

The existing regulatory documents on estimation of wave scours behind vertical-type structures take account of only frontal wave arrival. Though in most cases of real structures waves arrive at an angle to a structure. The kinematics of the formed wave field and as a result the interaction with the structure and the foundation soil differ from that of frontal waves. The work is devoted to investigation of local scour due to the influence of oblique waves. The main aim of the article is to define the features of the formation of the local scour due to oblique waves in front of breakwater and to define its difference from local scour caused by frontal waves. In order to study a local scour experiments have been conducted in a wave basin. As a result of the experiments the shape and depth of the scour were obtained. Significant differences of scour formation caused by frontal and oblique waves at the breakwater were found out. The scoured hole caused by oblique waves looks like a line directed along the walls, in contrast to the scour caused by the influence of the standing waves. It was found out that in case of smaller angle of wave arrival to the breakwater the depth and width of scoured hole increase. The experimental investigations also showed that the size of soil particles influence the formation of scour hole.

DOI: 10.22227/1997-0935.2016.9.108-118

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