Free Surface Reconstruction for Phase Accurate Irregular Wave Generation

Aggarwal, Ankit; Pákozdi, Csaba; Bihs, Hans; Myrhaug, Dag; Chella, Mayilvahanan Alagan

doi:10.3390/jmse6030105

Cited by 17 publications

(9 citation statements)

References 63 publications

(71 reference statements)

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“…The phase‐resolved numerical wave tank REEF3D (Bihs et al, 2016)—verified with field measurements—offers spatiotemporal distributions of oscillatory flow velocities and other relevant hydraulic variables in the near‐bank area. Three short sections of different intensities were simulated based on field measurements of an actual wave event using the wave reconstruction method (Aggarwal et al, 2018), resulting in phase accurate irregular wave hydrodynamics. Although wave heights during the analyzed sections ( H rms = 2.2–9.3 cm) covered the usually observable range of magnitudes for this section of the Danube (Fleit et al, 2016, 2019), the waves are considered relatively mild compared to 60 cm high ship‐induced waves measured on the Austrian Danube (Liedermann et al, 2014) or the Mississippi River (Bhowmik, Soong, Reichelt, & Seddik, 1991).…”

Section: Discussionmentioning

confidence: 99%

“…In the present simulations, a flatbed wave generation zone was located in the first section of the computational domain. The end of this initial zone was the location of the pressure sensor; thus, wave generation could be adjusted to the field data using the wave reconstruction method (Aggarwal, Pákozdi, Bihs, Myrhaug, & Alagan Chella, 2018). The measured (calculated) surface elevation time series were decomposed via FFT, from which the irregular wave train could be reconstructed at the inlet boundary through superposing each individual linear wave component ( N ) based on their amplitude, angular frequency, and phase, according to linear wave theory:

{(η (z, t)|}_{x = 0} = \sum_{i = 1}^{N} A_{i} \cos ((), ε_{i} - ω_{i} t)

{(u (z, t)|}_{x = 0} = \sum_{I = 1}^{N} A_{i} ω_{i} \frac{\cosh ((), k_{i} ((), z + d))}{\sinh ((), k_{i} d)} \cos ((), ε_{i} - ω_{i} t)

{(w (z, t)|}_{x = 0} = \sum_{I = 1}^{N} A_{i} ω_{i} \frac{\sinh ((), k_{i} ((), z + d))}{\sinh ((), k_{i} d)} \sin ((), ε_{i} - ω_{i} t)

where A i is the amplitude, k i is the wave number, ω i is the angular frequency, d is the total water depth, z is the signed distance of the point of interest from the mean free surface, and ε i is the phase of each ( i = 1…N ) wave components.…”

Section: Methodsmentioning

confidence: 99%

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A numerical modeling‐based predictive methodology for the assessment of the impacts of ship waves on YOY fish

Fleit

Hauer

Baranya

2020

River Research & Apps

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The effects of inland navigation on the aquatic ecosystem are numerous. One of the most relevant impacts from the ecohydraulic point of view is ship‐induced waves, resulting in the local and temporary alteration of the hydrodynamic regime, especially in shallow water areas. In this paper, a novel hydrodynamic modeling‐based evaluation framework is presented and tested for the prediction of habitat use and drift risk of juvenile fish during wave events of different intensities. A vertically resolved numerical wave tank was built up using field measurements of a real vessel‐generated wave event from the Hungarian Danube. High‐frequency pressure time series were utilized to numerically reproduce the phase accurate wave trains, while acoustic Doppler velocity time series were exploited for the verification of the model. Results of the spatiotemporally resolved hydrodynamic model were combined with data from the literature to explore a case study of juvenile Nase (Chondrostoma nasus). Results highlighted the significant horizontal extension (10–15 m) of the area exposed to decreased habitat suitability and increased drift risk. Moreover, the model revealed significant vertical variabilities in the investigated near‐bank area as well, emphasizing the relevance of depth resolved hydrodynamic modeling in ecohydraulic investigations.

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Section: Discussionmentioning

confidence: 99%

{(η (z, t)|}_{x = 0} = \sum_{i = 1}^{N} A_{i} \cos ((), ε_{i} - ω_{i} t)

{(u (z, t)|}_{x = 0} = \sum_{I = 1}^{N} A_{i} ω_{i} \frac{\cosh ((), k_{i} ((), z + d))}{\sinh ((), k_{i} d)} \cos ((), ε_{i} - ω_{i} t)

{(w (z, t)|}_{x = 0} = \sum_{I = 1}^{N} A_{i} ω_{i} \frac{\sinh ((), k_{i} ((), z + d))}{\sinh ((), k_{i} d)} \sin ((), ε_{i} - ω_{i} t)

Section: Methodsmentioning

confidence: 99%

A numerical modeling‐based predictive methodology for the assessment of the impacts of ship waves on YOY fish

Fleit

Hauer

Baranya

2020

River Research & Apps

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“…Nevertheless, the authors believe that boundary conditions for the wave generation could be further improved to take account for the already emphasized transient nature of the wave events. This could be either done through directly reproducing the measured wave events with the so‐called wave reconstruction method (see Aggarwal, Cs, Bihs, Myrhaug, & Chella, ) or through using spectrograms as inlet boundary conditions. The validated model offers a numerical wave tank providing the detailed spatial distribution of relevant hydrodynamic variables, such as the flow velocities or the turbulent kinetic energy.…”

Section: Discussionmentioning

confidence: 99%

A practical framework to assess the hydrodynamic impact of ship waves on river banks

Fleit

Baranya

Krámer

et al. 2019

River Research & Apps

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The temporal alteration of the hydrodynamic regime in rivers due to navigation has significant effects on riverine ecosystems. Most of the key mechanisms and interactions between hydrodynamic and ecological variables have already been revealed; however, the quantitative evaluation of biotic and abiotic variables still stands a challenge. This paper aims to present a thorough, spatiotemporal framework, involving field and computational tools, for the assessment of wave hydrodynamics in the littoral zone of rivers, where its ecological relevance is the most significant. The temporal variation of significant wave heights is derived from high-frequency pressure measurements, offering a well-comparable statistical evaluation of individual wave events considering the duration of different wave intensities. Acoustic Doppler velocimetry (ADV) is used for the assessment of near-bank velocities, from which the secondary wave-related components have been filtered offering relevant validation data for numerical modelling. The small footprint of the ADVs is extended with up-to-date computational fluid dynamics modelling. Wave spectra derived from the pressure measurements are used as boundary conditions for phase-resolved irregular wave modelling with the level set method based numerical model REEF3D. The properly validated model offers the assessment of the most relevant hydrodynamic variables (e.g., velocity or turbulent kinetic energy) in a spatially extended manner, from which the hydrodynamic footprint of the wave events can be interpreted in a statistical fashion. The implementation of the proposed framework is illustrated through a case study at a Hungarian section of the Danube River.

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“…1c. The waves at a distance of -28 m from the wavemaker in the 2D NWT are reconstructed in the 3D NWT at x = -28 m (beginning of the 3D NWT) using the free surface reconstruction technique (Aggarwal et al, 2018b). The reconstructed waves in the 3D NWT are then identical to the waves in the 2D NWT.…”

Section: Computational Setupmentioning

confidence: 99%

Estimation of breaking wave properties and their interaction with a jacket structure

Aggarwal

Bihs

Shirinov

et al. 2019

Journal of Fluids and Structures

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The numerical investigation of breaking wave interaction with jacket type offshore wind turbine substructures is quite challenging due to multiple jacket members and the complicated hydrodynamics of breaking waves around and inside the jacket. The present study is focused on investigating breaking wave forces and hydrodynamics on a jacket using a computational fluid dynamics (CFD) based numerical model. The breaking wave forces on a jacket mounted on a slope are investigated in a numerical wave tank. The experimental and numerical free surface elevations and wave forces are compared to validate the numerical model. The breaker indices and geometric profile properties for different wave steepness cases are correlated with force peaks. Further, the effect of changing the jacket location with respect to the wave breaker is investigated for different jacket locations for different wave steepness cases. In general, the force peaks are maximum when the fully grown breaker tongue impacts the jacket legs with large momentum. The influence of the jacket location on the wave-induced impact force rise time for both force peaks is also investigated in detail. The statistical analysis shows that the lognormal distribution is suitable to predict the breaking wave force statistics. The complex free surface features including the wave breaker tongue, secondary wave jet, chute like phenomenon and rejoining of the secondary wave jet with the free surface are observed during the interaction of breaking waves with the jacket. The role of horizontal velocity components in estimating the peak wave loads is further explored both deterministically and probabilistically.

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Free Surface Reconstruction for Phase Accurate Irregular Wave Generation

Cited by 17 publications

References 63 publications

A numerical modeling‐based predictive methodology for the assessment of the impacts of ship waves on YOY fish

A numerical modeling‐based predictive methodology for the assessment of the impacts of ship waves on YOY fish

A practical framework to assess the hydrodynamic impact of ship waves on river banks

Estimation of breaking wave properties and their interaction with a jacket structure

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