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Results
Translational and Rotational Motion Measurement of a Spherical Particle in Hydraulic Collecting
Xiong, Hong (Chinese Academy of Sciences, Sanya) | Chen, Yuxiang (Chinese Academy of Sciences, Sanya) | Cheng, Hui (Chinese Academy of Sciences, Sanya) | Zhu, Hong (Chinese Academy of Sciences, Sanya) | Yu, Chunliang (Chinese Academy of Sciences, Sanya) | Zheng, Guodong (Chinese Academy of Sciences, Sanya) | Xing, Yiyang (Chinese Academy of Sciences, Sanya)
_ Research on the motion of particles in fluid conveying is significant for the mechanism study of the hydraulic collecting process in deep-ocean mining. Experiments were conducted in a water tank to measure the translational and rotational motion of spherical particles by developing a spherical detector with a built-in three-dimensional acceleration microsensor and a three-dimensional microgyroscope. The three-axis linear acceleration and angular velocity can be measured and stored by the detector. The attitude angle, defined as the spatial rotation of the detector coordinate system relative to the laboratory coordinate system and described via the Euler angle, is obtained with a quaternion algorithm and a Kalman filter. The method is validated with a 50 mm diameter spherical object by three respective tests. Finally, the detector is tested as a tracer particle in hydraulic collecting. Findings indicate that the method is capable of tracing the detailed behaviors of particles in hydraulic collecting. Introduction In the process of exploring and developing the ocean, human beings have found that the seabed contains extremely rich metal mineral resources, oil, natural gas hydrate, etc., which can be of many types, be found in huge reserves and high grades, and have great prospects for development and utilization (Lusty and Murton, 2018). A deep-sea mining system is an integrated unit of mining vessel, pipe, and mining vehicle on the seabed that picks up solid particles or alluvial forms of solids, including heavy mineral particles, from the deep seabed and transports the solid particles to the sea surface. The mineral particles are mostly spherical or ellipsoidal, with their long-axis length varying from 2 cm to 10 cm, and the hydraulic lifting process is the large particle solid-liquid two-phase flow (Li and Chen, 2003). The movement mechanism of particle-water mixture is the key to hydraulic lifting technology.
Numerical Study of Cavitation Noise Around NACA66 (MOD) Hydrofoil with Direct Volume Integration
Yu, Lianjie (Shanghai Jiao Tong University, Shanghai) | Zhou, Fuchang (Wuhan Second Ship Design and Research Institute, Wuhan) | Zhao, Weiwen (Shanghai Jiao Tong University, Shanghai) | Wan, Decheng (Shanghai Jiao Tong University, Shanghai)
_ Underwater noise (URN) is the focus of academic research, and cavitation is an important source of underwater noise. This paper takes NACA66 (mod) two-dimensional hydrofoil as the research object and uses the open-source software OpenFOAM to simulate the sheet cavitation and sound field. The turbulence model is DDES, and the cavitation model is the Schnerr-Sauer model. The sound field is predicted by the FW-H formulation. Unlike the traditional method, this paper solves the quadrupole term (nonlinear term) by direct volume integration, so the nonlinear term can be predicted more accurately. At the same time, a new method of changing sound wave velocity is proposed considering the two-phase medium problem caused by cavitation. Four methods are compared, including two-phase volume integration, direct volume fraction, object surface integration, and penetrable formulation. It is found that the influence of two-phase flow is greater near the closure area of the cavity, which needs to be considered separately. The linear sound shows dipole directivity and the nonlinear component exhibits quadrupole characteristics. Introduction Underwater noise not only causes harm to marine life, but also affects the stealth of military equipment. The International Maritime Organization (IMO) issued non-mandatory noise standards for commercial ships (IMO, 2014). More and more attention has been paid to the acoustic environment. At this stage, the prediction of such noise becomes a hot topic (Deane and Stokes, 2010; Ianniello et al., 2013; Bensow and Liefvendahl, 2016).
- North America > United States (0.46)
- Asia > China (0.30)
- Transportation > Marine (1.00)
- Energy > Oil & Gas > Upstream (1.00)
Inside a Beach Drainage System: A Three-Dimensional Modeling
Fischione, Piera (University of Rome “Tor Vergata” Rome) | Celli, Daniele (University of L'Aquila, L'Aquila) | Pasquali, Davide (University of L'Aquila, L'Aquila) | Barajas, Gabriel (Instituto de Hidraulica Ambiental, Universidad de Cantabria (IHCantabria) Santander) | Di Paolo, Benedetto (Instituto de Hidraulica Ambiental, Universidad de Cantabria (IHCantabria) Santander) | Lara, Javier L. (Instituto de Hidraulica Ambiental, Universidad de Cantabria (IHCantabria) Santander)
_ The capabilities of computational fluid dynamics (CFD) to investigate detailed aspects of a physical phenomenon are here used to study the drainage efficiency of a beach drainage system (BDS)—namely, a low-environmental impact tool for shoreline stabilization. One of the advantages of CFD is its capability to investigate aspects that otherwise would be more difficult to measure experimentally. In this study, a three-dimensional CFD model was used to investigate what happens inside a drain when it is buried in a simplified fine porous domain, when an oscillating groundwater table, forced by regular waves, filters into a draining pipe. The model used was the OpenFOAM® solver IHFOAM, which solves the volume-averaged Reynolds-averaged Navier-Stokes equations to simulate flow through fine porous media such as the one in a sandy beach. A parametric study was carried out with respect to the porous medium and the draining surface characteristics as well as the flow regime inside the BDS. Different solutions on the draining surface were considered—namely, different arrangements of the holes through which water flows. Introduction This paper deals with the numerical modeling of a drain inside a fine porous medium forced by means of regular waves—that is, regular periodic oscillations of the groundwater. The proposed approach in this work is to reproduce by means of three-dimensional (3D) simulations a small case numerical test of a beach drainage system (BDS) (Fischione et al., 2021). The idea of beach dewatering was developed based on the interaction between swash zone hydrodynamics and groundwater dynamics. Its functioning relies on the interaction between groundwater level and swash zone sediment transport. BDS is a low-environmental impact tool that is thought to stabilize the shoreline, at least coupled with other methods such as beach nourishment (Di Risio et al., 2010) or coupled with other structures (Saponieri et al., 2018) to guarantee economical and efficient performances. It consists of a series of buried pipes that gravitationally or by means of a pumping system aims to locally lower the groundwater table and discourage the transport of sediment particles mobilized by the waves. It is a system that has been investigated over the decades (Grant, 1948; Chappell et al., 1979; Damiani et al., 2011) by both field experiences (e.g., Curtis et al., 1997; Bain et al., 2016) all over the world (Vicinanza et al., 2010) and means of experimental installations (e.g., Oh and Dean, 1994; Contestabile et al., 2012). It has been viewed as a possible alternative soft engineering method to counteract erosion because its low visual impact. Nevertheless, different and controversial results have been obtained from its application; hence, progressively, it has not been preferred to other methods (Fischione et al., 2022), also because the field experience results showed site-dependent performances (i.e., Vicinanza et al., 2010; Bain et al., 2016). For the sake of exhaustiveness, in the study of BDS, some technical aspects have been neglected so far (e.g., the hydraulic behavior of the pipes, their hydraulic efficiency, and some aspects that are proper to the hydraulic constructions rather than the coastal field), with a consequent lack of clear guidelines for its application. To face these aspects, the use of computational fluid dynamics (CFD) is suitable to investigate a domain and phenomena that are fully three-dimensional and nonlinear.
- Europe > Italy (0.29)
- North America > United States (0.28)
- Europe > Spain (0.28)
Numerical Comparative Study on Violent Wave Interactions with a Curved Seawall
Chen, Shuling (School of Naval Architecture and Ocean Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu) | Hu, Xiao (School of Naval Architecture and Ocean Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu) | Cui, Fuyin (School of Naval Architecture and Ocean Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu) | Wang, Wei (School of Naval Architecture and Ocean Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu)
_ The seawall is a classic structure for coastal protection. The ability to predict the wave loading and runup on the seawall plays a critical role in the design of the seawall, particularly in a high sea state and/or during a storm condition involving wave breaking and violent wave impact. This paper contributes to the numerical comparative study organized by the International Hydrodynamics Committee at the 32nd International Ocean and Polar Engineering Conference (ISOPE 2022), in which the wave load on a curved seawall with different scales was considered. The computational fluid dynamic software STAR-CCM+ was used to predict the wave elevations and wave-induced pressure on the seawall, as well as to quantify the turbulence effects through comparing the results from a laminar flow simulation and the corresponding large eddy simulation. It can be concluded that the results of the present study can reasonably capture the feature of the wave impact observed in the experimental data. More important, the results confirm that the turbulence effect is insignificant during the impact for both small-scale and full-scale modeling. Introduction As a classic coastal protection infrastructure, the seawall has been widely used in practice. The most critical parameters to be considered in seawall design are the maximum wave loading and runup on the seawall. The former is linked with the structural safety of the seawall, and the latter contributes to the evaluation of the probability of overtopping and coastal flooding. Great effort has been devoted to the design and optimisation of the seawall geometry aiming to reduce the wave loads and runup. Typical approaches include the curved front (e.g., De Chowdhury et al., 2017) and vertical seawall with parapets installed on the top (e.g., Castellino et al., 2018; Dong et al., 2021). The latter has been proven to be an effective design to avoid overtopping through diverting the wave toward the seaward direction (Ravindar et al., 2019, 2021, 2022; Stagonas et al., 2020; Ravindar and Sriram, 2021). The recurved parapet (e.g., Ravindar et al., 2022) in particular has attracted interest because it has the benefit of reducing the wave loads.
- Asia > China (0.28)
- North America > United States > California (0.28)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics (0.86)
- Data Science & Engineering Analytics > Information Management and Systems (0.68)
- Reservoir Description and Dynamics > Reservoir Simulation (0.68)
- Production and Well Operations > Well & Reservoir Surveillance and Monitoring > Production logging (0.48)
_ The interaction of a breaking wave and a vertical seawall with a recurved parapet attached is investigated using a three-dimensional parallel model based on a constrained interpolation profile (CIP); the model is accelerated by high-performance computation using the message passing interface algorithm and open multiprocessing algorithm. The Navier– Stokes equations are solved using the projection method. A high-order finite difference method, the CIP method, is applied for the convection term. In a volume of fluid method, the tangent of hyperbola for interface capturing with a slope weighting method is used to simulate the variation of the free surface. Numerical results are compared with the experimental results, and good agreement is obtained. The wave impact pressures on the vertical seawall attached with the recurved parapet are accurately predicted. Moreover, the large deformation of the wave profiles of the transient wave impact process is finely simulated, which can help us better assess the reliability and survivability of these structures in the presence of extreme loads. Introduction As the global climate warms and sea levels continue to rise, it is very important to reduce the damage of overtopping and slamming load to the vertical seawall in extreme events. A sea-facing overhang structure, the so-called recurved parapet, can be attached to a new or existing vertical seawall. The overhang structure, which forces the upward rushing water and towering waves to curl toward the sea, can release the energy of the waves back into the sea and reduce the damage to the structure. This process involves problems such as wave breaking, air trapping, and wave slamming (Ravindar et al., 2019). How to accurately predict the impact load and wave climb is a challenging topic both for the effectiveness of numerical models and for the accuracy of physical experiments (Liu et al., 2020).
Numerical Study of Three-Dimensional Water Entry Problems of Complex Structures Using Particle Method
Deng, Rui (Sun Yat-sen University, Zhuhai) | Lyu, Hong-Guan (Sun Yat-sen University, Zhuhai) | Sun, Peng-Nan (Sun Yat-sen University, Zhuhai) | Huang, Xiao-Ting (Sun Yat-sen University, Zhuhai) | Wu, Tie-Cheng (Sun Yat-sen University, Zhuhai)
_ Water entry problems are critical in hydrodynamics because of strong impact pressure and complex structural motions in such phenomena. This paper is dedicated to presenting a fully 3-D smoothed particle hydrodynamics (SPH) model for the water entry problems of complex structures. First, the adopted SPH model is briefly introduced. Subsequently, two water entry benchmarks are performed to validate the accuracy and stability of the utilized SPH model. Furthermore, one typical engineering application related to aircraft ditching is performed. The present SPH model is clearly demonstrated to possess satisfactory accuracy and stability for simulating water entry problems. Introduction Water entry problems of complex structures are one of the most important topics in hydrodynamics because such phenomena involve extensive complex physical processes (e.g., hydroelasticity, turbulence, cavitation, multiphase effects, and fluid–structure interaction (FSI)) (Truscott et al., 2014). For such complex FSI processes, experimental methods are one of the most reliable strategies to investigate water entry problems. Notwithstanding, two limitations block the wide use of this method in practical applications. One is that scaling effects from model tests are inevitably encountered when transforming the model measurements into full-scale data (Lugni et al., 2021). The second is that physical tests are always expensive, and many extreme case conditions are hard to reproduce in a laboratory. Therefore, the technique of computational fluid dynamics (CFD) can be a more feasible strategy in engineering designs. In terms of CFD, traditional Eulerian mesh-based methods (e.g., finite volume (FV)) have been widely adopted to simulate the water entry problems for different simple objects such as cylinders (Hou et al., 2018), wedges (K Wang et al., 2021), and spheres (Shen et al., 2022). However, applying them for complex structures with complex geometrical surfaces is relatively rare. In fact, several researchers have explored this topic by using some mature commercial packages (e.g., STAR-CCM+) (Tregde and Nestegård, 2014; Tregde, 2015; Huang et al., 2021), finding that some violent and nonlinear water surface behaviors (e.g., splashing and breaking) are hard to accurately capture because of the inherent mass nonconservation property of the FV method. Besides, although the so-called overset mesh (OM) technique can be used to realize the six-degrees-of-freedom (6DoF) motion of rigid objects in the FV framework, it is well-known that serious field discontinuities exist at the overset–background interface where flow information is exchanged between these two regions. Such a characteristic could somewhat reduce the accuracy of the FV results.
- North America (0.46)
- Asia > China > Guangdong Province (0.28)
_ In this paper, the low-speed water entry of four projectiles with various head types is numerically studied by using an improved multiphase moving particle semi-implicit (MPS) method. The projectiles are composed of a solid circular cylinder with L/D=4.5 and different head shapes, including a hemispherical head and three cone-shaped heads (90°~150°). During the water entry of these free-falling projectiles, splashing water, the deformed free surface, and the cavity evolution behind the cylinder are presented, which show agreement with experimental data. The vertical velocities and forces obtained by the multiphase MPS method are given. The influences of varying head shapes on the motion of the projectiles and the generation and closure of cavities are analyzed. Introduction There widely exist water entry phenomena in the defense industry and ocean engineering with a fluid-structure interaction and multiphase flow. Water entry by a projectile involving cavity formation and collapse has been investigated theoretically. For example, Lee et al. (1997) developed an analytical model for the cavity dynamics to study the high-speed water entry of a sphere. It was indicated that a cavity can be characterized as a deep closure prior to closure at the surface for high-speed water entry, and the time of deep closure was constant, which was independent of the impact velocity. Mirzaei et al. (2020) proposed a transient model to predict the shape of the oblique water entry cavity for a cylindrical projectile at different angles. The predicted projectile attitude and the trajectory of the projectile agreed well with the experimental data. Experimental studies on both low-speed and high-speed water entry with cavities have also been extensively carried out by using high-speed cameras. For example, Truscott and Techet (2009a, 2009b) and Techet and Truscott (2011) experimentally studied the trajectories, forces, and cavity formation behind spinning hydrophobic and hydrophilic spheres after water entry in the MIT Experimental Hydrodynamics Laboratory at the Massachusetts Institute of Technology. The splash and cavity of spheres’ water entry with varying spin rates and impact velocities were compared. Yang et al. (2014) conducted a series of experiments of low-speed water entry of projectiles with different head types. The snapshots of the cavity-running phase under different velocity and entry angle conditions were recorded by high-speed photography, and the influences of head types on the characteristics of cavity formation and closure were analyzed. The oblique high-speed water entry of projectiles was investigated by Song et al. (2020). The deflection of trajectories and the evolution of supercavities were analyzed.
- Asia > China (0.69)
- North America > United States > Massachusetts (0.24)
_ Seabed stability around submarine pipelines under wave-plus-current loading is one of the major issues in offshore projects. Unlike previous works that focused mainly on the evaluation of the seabed response around a single pipeline, in this study, two pipelines in tandem will be considered. The previous model (PORO-FSSI-FOAM) will be adopted to investigate the effect of the gap ratios (G/D) of twin pipes on the wave and current-induced oscillatory seabed response. The numerical model is validated with the previous experimental data for two pipelines in tandem. Based on numerical examples, the following conclusions were found: (i) when the gap ratio (G/D) is greater than 1.25, the soil response beneath both pipelines is more significant than in the condition of a single body; and (ii) the maximum liquefaction depth appears to increase as ks and Sr decrease, and ks is more sensitive to the evolution of the liquefied zone. Introduction Pipelines have been one of the essential associated installations for the oil and gas industry, which have been used for the transportation of oil and gas from offshore to onshore. Since the first offshore pipeline was built by Brown Root to carry oil in 1954, submarine pipeline networks have been regarded across the globe as the “lifelines” of the oil industry (Sumer and Fredsøe, 2002). The existence of a submarine pipeline does not only alter the nearby flow morphology, but also enhances the surrounding seafloor instability (including soil liquefaction, scour, and shear failure) and ultimately causes damage or failure of the pipeline (Sumer, 2014).
- Europe (0.93)
- North America > United States (0.46)
_ The paper presents a high-order consistent incompressible smoothed particle hydrodynamics (ISPH) fluid model for accurate simulation of ocean engineering problems. The high-order consistent discretization schemes on differential operators are derived through consideration of Taylor-series expansion up to second-order differential terms. The derived consistent discretization schemes are applied to the calculations of a Laplacian term of pressure in the Poisson pressure equation (PPE) and pressure gradient term in the momentum equation. To enhance and ensure the accuracy, stability, and conservation property of the model, the enhanced schemes developed by our research team—namely, the higher-order source term, error-compensating source term, and dynamic stabilizer schemes—are also incorporated. The proposed high-order consistent ISPH fluid model is validated through reproduction of a set of numerical examples. Introduction Lagrangian meshfree computational methods, or the so-called particle methods such as smoothed particle hydrodynamics (SPH; Gingold and Monaghan, 1977) or incompressible SPH (ISPH; Shao and Lo, 2003), have recently been attracting a lot of interest in various engineering fields. Thanks to their Lagrangian meshfree description of motion, the particle methods possess great advantages— for example, being free from calculation of an advection term and stable/natural tracking of complex moving boundaries. In the field of ocean engineering, one can easily find a number of existing applications of particle methods toward violent free-surface fluid flow and its interaction with rigid/deformable structures, as comprehensively reviewed in Luo et al. (2021) and Gotoh et al. (2021).
Experimental and Numerical Study of Gas Outburst with Soil Under Gas Expansion
Liu, Danning (University of Chinese Academy of Sciences, Beijing) | Li, Peng (Chinese Academy of Sciences, Beijing) | Zhang, Xuhui (Chinese Academy of Sciences, Beijing) | Lu, Xiaobing (Chinese Academy of Sciences, Beijing) | Qiao, Jiyan (Chinese Academy of Sciences, Beijing) | Leng, Zhenpeng (Chinese Academy of Sciences, Beijing) | Zhang, Yan (Chinese Academy of Sciences, Beijing)
Abstract The outburst fragmentation of soil caused by the dissociation of the gas hydrate was studied via experiments and numerical simulation. The dense discrete particle model combined with the kinetic theory of granular flow was presented to reveal the outburst morphology of soil, considering the interphase forces and frictional effect between soil particles. The numerical simulation results in geometric features are consistent with the experimental results. The diameter of the gas outburst with soil can be predicted by the model, and the rule of the particle velocity can be obtained by the simulation. Moreover, the effects of initial gas pressure and thicknesses of the overlying layer on the occurrence of gas outbursts were investigated in the experiments. Introduction Gas hydrate (GH) has become an important strategic energy source in China because of its large reserve and little pollution. Many countries in the world have accelerated the exploration and development of GH. However, concerns about possible geological disasters, even hazard chains caused by exploitation activities, are increasing. The dissociation of GH from hydrate-bearing sediments during exploration can cause the softening of soils and the formation of excess pore gas pressure (Zhang et al., 2015). The hydrate sediments become a gas–liquid–solid phase slurry structure after the hydrate dissociation (Nair et al., 2019). If the accumulated pressure after the hydrate dissociation equals or exceeds the soil’s resistance, plastic failure or gas outburst can occur.
- Asia > China (0.67)
- North America > United States > California (0.46)