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http://hdl.handle.net/10985/22706
Direct Numerical Simulation of Shallow Water Breaking Waves Generated by Wave Plate
LIU, Shuo; WANG, Hui; COUTIER-DELGOSHA, Olivier; BAYEUL-LAINÉ, Annie-Claude
We present direct numerical simulation of breaking waves in shallow water generated by the wave plate. The open-source Basilisk solver is used to solve the incompressible, variable-density, twophase Navier-Stokes equations with surface tension. The air-water interface is advected using a momentum-conservative Volume-of-Fluid (MCVOF) scheme. The surface tension is treated with the balanced-force technique. Adaptive mesh refinement (AMR) scheme is employed for computational efficiency, concentrating the computational resource on the significant solution area. By reconstructing the piston-type wave plate numerically, we realize high-fidelity simulation of experimental waves under the wide-ranging motions of the wave plate.
The relationship between varying maximum wave plate speed and associated maximum wave height before breaking is investigated, the onset of wave breaking as a function of the ratio of wave height to water depth is determined to distinguish between non-breaking waves, spilling breakers, and plunging breakers. A typical plunging breaking wave with a large ratio of wave height to water depth is initialized to recognize the wave breaking and air entrainment process. We obtain good collapse of the simulated free-surface evolution and velocity fields with respect to the experiment. The shape and size of air entrapped at impact by plunging jet matches closely the experimental observation during wave breaking. The time-evolving energy budget and bubble characteristics under breaking waves are further discussed based on the numerical results.
Thu, 01 Sep 2022 00:00:00 GMThttp://hdl.handle.net/10985/227062022-09-01T00:00:00ZLIU, ShuoWANG, HuiCOUTIER-DELGOSHA, OlivierBAYEUL-LAINÉ, Annie-ClaudeWe present direct numerical simulation of breaking waves in shallow water generated by the wave plate. The open-source Basilisk solver is used to solve the incompressible, variable-density, twophase Navier-Stokes equations with surface tension. The air-water interface is advected using a momentum-conservative Volume-of-Fluid (MCVOF) scheme. The surface tension is treated with the balanced-force technique. Adaptive mesh refinement (AMR) scheme is employed for computational efficiency, concentrating the computational resource on the significant solution area. By reconstructing the piston-type wave plate numerically, we realize high-fidelity simulation of experimental waves under the wide-ranging motions of the wave plate.
The relationship between varying maximum wave plate speed and associated maximum wave height before breaking is investigated, the onset of wave breaking as a function of the ratio of wave height to water depth is determined to distinguish between non-breaking waves, spilling breakers, and plunging breakers. A typical plunging breaking wave with a large ratio of wave height to water depth is initialized to recognize the wave breaking and air entrainment process. We obtain good collapse of the simulated free-surface evolution and velocity fields with respect to the experiment. The shape and size of air entrapped at impact by plunging jet matches closely the experimental observation during wave breaking. The time-evolving energy budget and bubble characteristics under breaking waves are further discussed based on the numerical results.Dynamics of high-speed drop impact on deep liquid pool
http://hdl.handle.net/10985/22707
Dynamics of high-speed drop impact on deep liquid pool
WANG, Hui; LIU, Shuo; COUTIER-DELGOSHA, Olivier; BAYEUL-LAINÉ, Annie-Claude
In this work, high-speed drop impact onto deep volume of the same liquid is numerically studied in 3D using Direct Numerical Simulation (DNS). The numerical results are compared with the previous experimental works by Murphy et al. [1]. Most of the distinctive features during the impact, including the evolution of the crown and cavity, the ligaments emanating from the rim of the crown, the formation of the bubble canopy, the central spiral jet that pierces through the bottom of the cavity and the subsequent broad upward jet, are correctly reproduced. The trajectory of the upper rim of the crown as well as the depth and width of the subsurface cavity are tracked during the simulation. Very reliable quantitative agreements between numerical and experimental data are obtained with respect to the time evolution of the crown rim and cavity dimensions. The simulation shows very good qualitative and quantitative agreement against the available experimental data, which enables the further investigation of the internal mechanisms of drop impact in the future
Thu, 01 Sep 2022 00:00:00 GMThttp://hdl.handle.net/10985/227072022-09-01T00:00:00ZWANG, HuiLIU, ShuoCOUTIER-DELGOSHA, OlivierBAYEUL-LAINÉ, Annie-ClaudeIn this work, high-speed drop impact onto deep volume of the same liquid is numerically studied in 3D using Direct Numerical Simulation (DNS). The numerical results are compared with the previous experimental works by Murphy et al. [1]. Most of the distinctive features during the impact, including the evolution of the crown and cavity, the ligaments emanating from the rim of the crown, the formation of the bubble canopy, the central spiral jet that pierces through the bottom of the cavity and the subsequent broad upward jet, are correctly reproduced. The trajectory of the upper rim of the crown as well as the depth and width of the subsurface cavity are tracked during the simulation. Very reliable quantitative agreements between numerical and experimental data are obtained with respect to the time evolution of the crown rim and cavity dimensions. The simulation shows very good qualitative and quantitative agreement against the available experimental data, which enables the further investigation of the internal mechanisms of drop impact in the futureAnalysis of high-speed drop impact onto deep liquid pool
http://hdl.handle.net/10985/24301
Analysis of high-speed drop impact onto deep liquid pool
WANG, Hui; LIU, Shuo; BAYEUL-LAINÉ, Annie-Claude; MURPHY, David; KATZ, Joseph; COUTIER-DELGOSHA, Olivier
The present work is devoted to the analysis of drop impact on a deep liquid pool, focusing on the high-energy splashing regimes caused by large raindrops at high velocities. Such cases are characterized by short time scales and complex mechanisms, thus they have received very little attention until now. The BASILISK open-source solver is used to perform three-dimensional direct numerical simulations. The capabilities of octree adaptive mesh refinement techniques enable capturing of the small-scale features of the flow, while the volume of fluid approach combined with a balanced-force surface-tension calculation is applied to advect the volume fraction of the liquids and reconstruct the interfaces. The numerical results compare well with experimental visualizations: both the evolution of crown and cavity, the emanation of ligaments, the formation of bubble canopy and the growth of a downward-moving spiral jet that pierces through the cavity bottom, are correctly reproduced. Reliable quantitative agreements are also obtained regarding the time evolution of rim positions, cavity dimensions and droplet distributions through an observation window. Furthermore, simulation gives access to various aspects of the internal flows, which allows us to better explain the observed physical phenomena. Details of the early-time dynamics of bubble ring entrapment and splashing performance, the formation/collapse of bubble canopy and the spreading of drop liquid are discussed. The statistics of droplet size show the bimodal distribution in time, corroborating distinct primary mechanisms of droplet production at different stages.
Sun, 01 Oct 2023 00:00:00 GMThttp://hdl.handle.net/10985/243012023-10-01T00:00:00ZWANG, HuiLIU, ShuoBAYEUL-LAINÉ, Annie-ClaudeMURPHY, DavidKATZ, JosephCOUTIER-DELGOSHA, OlivierThe present work is devoted to the analysis of drop impact on a deep liquid pool, focusing on the high-energy splashing regimes caused by large raindrops at high velocities. Such cases are characterized by short time scales and complex mechanisms, thus they have received very little attention until now. The BASILISK open-source solver is used to perform three-dimensional direct numerical simulations. The capabilities of octree adaptive mesh refinement techniques enable capturing of the small-scale features of the flow, while the volume of fluid approach combined with a balanced-force surface-tension calculation is applied to advect the volume fraction of the liquids and reconstruct the interfaces. The numerical results compare well with experimental visualizations: both the evolution of crown and cavity, the emanation of ligaments, the formation of bubble canopy and the growth of a downward-moving spiral jet that pierces through the cavity bottom, are correctly reproduced. Reliable quantitative agreements are also obtained regarding the time evolution of rim positions, cavity dimensions and droplet distributions through an observation window. Furthermore, simulation gives access to various aspects of the internal flows, which allows us to better explain the observed physical phenomena. Details of the early-time dynamics of bubble ring entrapment and splashing performance, the formation/collapse of bubble canopy and the spreading of drop liquid are discussed. The statistics of droplet size show the bimodal distribution in time, corroborating distinct primary mechanisms of droplet production at different stages.Wave statistics and energy dissipation of shallow-water breaking waves in a tank with a level bottom
http://hdl.handle.net/10985/24761
Wave statistics and energy dissipation of shallow-water breaking waves in a tank with a level bottom
LIU, Shuo; WANG, Hui; BAYEUL-LAINÉ, Annie-Claude; LI, Cheng; KATZ, Joseph; COUTIER-DELGOSHA, Olivier
The present study focuses on two-dimensional direct numerical simulations of shallow-water breaking waves, specifically those generated by a wave plate at constant water depths. The primary objective is to quantitatively analyse the dynamics, kinematics and energy dissipation associated with wave breaking. The numerical results exhibit good agreement with experimental data in terms of free-surface profiles during wave breaking. A parametric study was conducted to examine the influence of various wave properties and initial conditions on breaking characteristics. According to research on the Bond number (
$Bo$
, the ratio of gravitational to surface tension forces), an increased surface tension leads to the formation of more prominent parasitic capillaries at the forwards face of the wave profile and a thicker plunging jet, which causes a delayed breaking time and is tightly correlated with the main cavity size. A close relationship between wave statistics and the initial conditions of the wave plate is discovered, allowing for the classification of breaker types based on the ratio of wave height to water depth,
$H/d$
. Moreover, an analysis based on inertial scaling arguments reveals that the energy dissipation rate due to breaking can be linked to the local geometry of the breaking crest
$H_b/d$
, and exhibits a threshold behaviour, where the energy dissipation approaches zero at a critical value of
$H_b/d$
. An empirical scaling of the breaking parameter is proposed as
$b = a(H_b/d - \chi _0)^n$
, where
$\chi _0 = 0.65$
represents the breaking threshold and
$n = 1.5$
is a power law determined through the best fit to the numerical results.
Wed, 01 Nov 2023 00:00:00 GMThttp://hdl.handle.net/10985/247612023-11-01T00:00:00ZLIU, ShuoWANG, HuiBAYEUL-LAINÉ, Annie-ClaudeLI, ChengKATZ, JosephCOUTIER-DELGOSHA, OlivierThe present study focuses on two-dimensional direct numerical simulations of shallow-water breaking waves, specifically those generated by a wave plate at constant water depths. The primary objective is to quantitatively analyse the dynamics, kinematics and energy dissipation associated with wave breaking. The numerical results exhibit good agreement with experimental data in terms of free-surface profiles during wave breaking. A parametric study was conducted to examine the influence of various wave properties and initial conditions on breaking characteristics. According to research on the Bond number (
$Bo$
, the ratio of gravitational to surface tension forces), an increased surface tension leads to the formation of more prominent parasitic capillaries at the forwards face of the wave profile and a thicker plunging jet, which causes a delayed breaking time and is tightly correlated with the main cavity size. A close relationship between wave statistics and the initial conditions of the wave plate is discovered, allowing for the classification of breaker types based on the ratio of wave height to water depth,
$H/d$
. Moreover, an analysis based on inertial scaling arguments reveals that the energy dissipation rate due to breaking can be linked to the local geometry of the breaking crest
$H_b/d$
, and exhibits a threshold behaviour, where the energy dissipation approaches zero at a critical value of
$H_b/d$
. An empirical scaling of the breaking parameter is proposed as
$b = a(H_b/d - \chi _0)^n$
, where
$\chi _0 = 0.65$
represents the breaking threshold and
$n = 1.5$
is a power law determined through the best fit to the numerical results.