scholarly journals Harbor Tranquility Analysis Method for using Boussinesq-typ. Nonlinear Wave Transformation Model

2008 ◽  
Vol 55 ◽  
pp. 796-800
Author(s):  
Katsuya HIRAYAMA
Keyword(s):  
Nonlinear Wave ◽  
Transformation Model ◽  
Wave Transformation ◽  
Analysis Method

Extreme Value Prediction on Decreasing Depth by Means of a Nonlinear Wave Transformation Model

2007 ◽  
Author(s):  
K. A. Belibassakis ◽  
Ch. N. Stefanakos ◽  
Y. G. Georgiou
Keyword(s):  
Time Series ◽  
Nonlinear Wave ◽  
Extreme Value ◽  
Second Order ◽  
Transformation Model ◽  
Wave Transformation ◽  
Series Data ◽  
Wave Spectra ◽  
Wave Parameters

In the present work a weakly nonlinear wave model originally developed by Rebaudengo Lando` et al (1996) is applied to the transformation of wave spectra from offshore to nearshore, and subsequently, it has been systematically applied to the derivation of long-term time series of spectral wave parameters on decreasing depth from corresponding offshore wave data. The derived long-term series of nearshore parameters have been used as input to a new method, recently developed by Stefanakos & Athanassoulis (2006), for calculating return periods of various level values from nonstationary time series data. The latter method is based on a new definition of the return period, that uses the MEan Number of Upcrossings of the level x* (MENU method), and it has been shown to lead to predictions that are more realistic than traditional methods. To examine the effects of bottom topography on the nearshore extreme value predictions, Roseau (1976) bottom profiles have been used for which analytical expressions are available concerning the reflection and transmission coefficients. A parametric (JONSWAP) model is used to synthesize offshore spectra from integrated parameters, which are then linearly transformed based on the previous transmission coefficient to derive first-order nearshore wave spectra. Second-order random sea states have been simulated by following the approach of Hudspeth & Chen (1979) (see also Langley 1987, Lando et al 1996), exploiting the quadratic transfer functions on decreasing depth to calculate the second-order nearshore spectra. Finally, wave parameters are extracted from the nearshore spectra by calculating the first few moments.

PHYSICAL INTERPRETATION OF WAVE BREAKING CRITERIA

2017 ◽  
Author(s):  
Sergey Kuznetsov ◽  
Sergey Kuznetsov ◽  
Yana Saprykina ◽  
Yana Saprykina ◽  
Boris Divinskiy ◽  
...  
Keyword(s):  
Nonlinear Wave ◽  
Wave Breaking ◽  
Second Harmonic ◽  
Vertical Axis ◽  
Breaking Waves ◽  
Wave Transformation ◽  
Spectral Structure ◽  
Similarity Parameter ◽  
Nonlinear Harmonics ◽  
The Waves

On the base of experimental data it was revealed that type of wave breaking depends on wave asymmetry against the vertical axis at wave breaking point. The asymmetry of waves is defined by spectral structure of waves: by the ratio between amplitudes of first and second nonlinear harmonics and by phase shift between them. The relative position of nonlinear harmonics is defined by a stage of nonlinear wave transformation and the direction of energy transfer between the first and second harmonics. The value of amplitude of the second nonlinear harmonic in comparing with first harmonic is significantly more in waves, breaking by spilling type, than in waves breaking by plunging type. The waves, breaking by plunging type, have the crest of second harmonic shifted forward to one of the first harmonic, so the waves have "saw-tooth" shape asymmetrical to vertical axis. In the waves, breaking by spilling type, the crests of harmonic coincides and these waves are symmetric against the vertical axis. It was found that limit height of breaking waves in empirical criteria depends on type of wave breaking, spectral peak period and a relation between wave energy of main and second nonlinear wave harmonics. It also depends on surf similarity parameter defining conditions of nonlinear wave transformations above inclined bottom.

scholarly journals Extended Elliptic Mild Slope Equation Incorporating the Nonlinear Shoaling Effect

2016 ◽  
Vol 23 (s1) ◽  
pp. 44-51 ◽  
Author(s):  
Qian-lu Xiao ◽  
Chun-hui Li ◽  
Xiao-yan Fu ◽  
Mei-ju Wang
Keyword(s):  
Dispersion Relation ◽  
Nonlinear Wave ◽  
Surf Zone ◽  
Wave Dispersion ◽  
Structure Design ◽  
Coastal Engineering ◽  
Wave Transformation ◽  
Flume Experiments ◽  
Mild Slope Equation ◽  
Wave Shoaling

Abstract The transformation during wave propagation is significantly important for the calculations of hydraulic and coastal engineering, as well as the sediment transport. The exact wave height deformation calculation on the coasts is essential to near-shore hydrodynamics research and the structure design of coastal engineering. According to the wave shoaling results gained from the elliptical cosine wave theory, the nonlinear wave dispersion relation is adopted to develop the expression of the corresponding nonlinear wave shoaling coefficient. Based on the extended elliptic mild slope equation, an efficient wave numerical model is presented in this paper for predicting wave deformation across the complex topography and the surf zone, incorporating the nonlinear wave dispersion relation, the nonlinear wave shoaling coefficient and other energy dissipation factors. Especially, the phenomenon of wave recovery and second breaking could be shown by the present model. The classical Berkhoff single elliptic topography wave tests, the sinusoidal varying topography experiment, and complex composite slopes wave flume experiments are applied to verify the accuracy of the calculation of wave heights. Compared with experimental data, good agreements are found upon single elliptical topography and one-dimensional beach profiles, including uniform slope and step-type profiles. The results indicate that the newly-developed nonlinear wave shoaling coefficient improves the calculated accuracy of wave transformation in the surf zone efficiently, and the wave breaking is the key factor affecting the wave characteristics and need to be considered in the nearshore wave simulations.

scholarly journals The Method for Evaluating Cross-Shore Migration of Sand Bar under the Influence of Nonlinear Waves Transformation

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 214
Author(s):  
Margarita Shtremel ◽  
Yana Saprykina ◽  
Berna Ayat
Keyword(s):  
Sediment Transport ◽  
Nonlinear Wave ◽  
Maximum Amplitude ◽  
Field Measurements ◽  
Wave Transformation ◽  
Sandy Bottom ◽  
Divergence Point ◽  
Sand Bar ◽  
Wave Induced ◽  
Second Wave

Sand bar migration on the gently sloping sandy bottom in the coastal zone as a result of nonlinear wave transformation and corresponding sediment transport is discussed. Wave transformation on the intermediate depth causes periodic exchange of energy in space between the first and the second wave harmonics, accompanied by changes in the wave profile asymmetry. This leads to the occurrence of periodical fluctuations in the wave-induced sediment transport. It is shown that the position of the second nonlinear wave harmonic maximum determines location of the divergence point of sediment transport on the inclined bottom profile, where it changes direction from the onshore to the offshore. Such sediment transport pattern leads to formation of an underwater sand bar. A method is proposed to predict the position of the bar on an underwater slope after a storm based on calculation of the position of the maximum amplitude of the second nonlinear harmonic. The method is validated on the base of field measurements and ERA 5 reanalysis wave data.

scholarly journals Re-design Breakwater di PPI Tulandale Berdasarkan Analisis Hidrodinamika dan Sedimentasi. (Hal. 30-41)

2019 ◽  
Vol 5 (3) ◽  
pp. 30
Author(s):  
Regina Eugeny Destin Wirawan ◽  
Yessi Nirwana Kurniadi ◽  
Fitri Suciaty
Keyword(s):  
Sediment Transport ◽  
Neap Tide ◽  
Spring Tide ◽  
Current Speed ◽  
Transformation Model ◽  
Wave Transformation ◽  
North East ◽  
South West ◽  
Result Show ◽  
Mike 21

ABSTRAKPangkalan Pendaratan Ikan Tulandale berada di Kabupaten Rote Ndao, Provinsi Nusa Tenggara Timur. Breakwater di PPI Tulandale tidak dapat melindungi kolam pelabuhan dari gelombang tinggi. Tujuan dari penelitian ini adalah re-design breakwater pada PPI Tulandale agar dapat melindungi kolam pelabuhan. Simulasi hidrodinamika, transpor sedimen dan transformasi gelombang dilakukan dengan bantuan perangkat lunak Mike 21 untuk 2 buah skenario. Pada skenario alternatif 1, mulut pelabuhan di perkecil menjadi 50 m dan skenario alternatif 2 pada kondisi breakwater eksisting ditambah bangunan breakwater tegak lurus garis pantai sepanjang 200 m. Simulasi dilakukan selama 15 hari. Hasil analisis pada pemodelan, kondisi arus saat pasang purnama dan perbani bergerak dari arah barat daya kearah timur laut dengan kecepatan 0,00–0,08 m/s untuk alternatif 1, sedangkan kecepatan arus alternatif 2 arus sebesar 0,08–0,16 m/s. Hasil pemodelan hidrodinamika, transpor sedimen dan transformasi gelombang menunjukan bahwa bentuk re-design breakwater pada alternatif 2 efektif untuk melindungi kolam pelabuhan di PPI Tulandale karena dapat mereduksi gelombang sebesar 46,7% dari gelombang diluar kolam pelabuhanKata kunci: re-design breakwater, hidrodinamika, sedimentasi ABSTRACTTulandale Fishing Port Tulandale is located in Rote Ndao district, The province of Nusa Tenggara Timur. The Breakwater in Tulandale Fishing Port could not protect the port basin from the height of waves. The aimed of this study is to re-design breakwater in Tulandale Fishing Port in order to protect the port basin. The Hydrodynamic, sediment transport and waves transformation simulation are applied in this study by using mike 21 software for 2 scenarios. In the first scenario, the port basin width is reduced to 50 m and the second scenario is using the existing breakwater condition with the added breakwater building Perpendicular along the coast line for 200m. The simulation run of 15 days. The result show that the condition during the spring tide and neap tide move from south west to north east with 0.00-0.08 m/s for first scenario, while the current speed for the second scenario is is 0.08-0.16 m/s. Hydrodynamic result, sediment transport and wave transformation model that the shape of re-design breakwater on the second scenario more effective to protect the port basin at The Tuandale Fishing Port because the wave decrease at 46.7% from outside the port basin.Keywords: re-design breakwater, hydrodynamics, sedimentation

Research on the Transformation of User's Implicit Knowledge to Design Knowledge in Product Design

2017 ◽  
Vol 5 (2) ◽  
pp. 243
Author(s):  
Sun Qiang ◽  
Hu Fei
Keyword(s):  
Product Design ◽  
Collaborative Design ◽  
Implicit Knowledge ◽  
Differential Method ◽  
Transformation Model ◽  
Design Knowledge ◽  
Analysis Method ◽  
Conversion Model ◽  
The Relationship ◽  
Process Dimension

The characteristics of the user’s implicit knowledge in product design and the relationship between the user’s implicit knowledge and design knowledge are discussed. The transformation model of user implicit knowledge to design knowledge is built. And the key technologies of it are analyzed. The four design dimensions which the transformation from user implicit knowledge to design knowledge is based on are proposed, namely, the design process dimension, the design object dimension, the organization dimension and the knowledge dimension. Taking household cleaner as an example, this paper utilizes the oral analysis method and the semantic differential method to analyze the transformation of user implicit knowledge to design knowledge, and validates the conversion model. It is helpful for improving the computer aided industrial design and household appliance products network collaborative design.

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