CFD Modeling of a Submersible in a Realistic Surfaced Sea State Condition for Predictions of Hydrodynamic Wave Impact Loading

2011 ◽  
Author(s):  
Minyee Jiang ◽  
David Drazen ◽  
Jack R. Lee
Keyword(s):  
Impact Loading ◽  
Impact Load ◽  
Fluid Dynamic ◽  
Scale Model ◽  
Cfd Modeling ◽  
Contributing Factors ◽  
Wave Impact ◽  
Water Line ◽  
Wave Slamming ◽  
Hydrodynamic Wave

Topside features on submersibles are subject to wave impact loading while surfaced. At the surface, operations are typically conducted at low to zero ship speeds so hydrodynamic loading is dominated by wave loading as opposed to bow/wave slamming which is typically evaluated for surface ships. The typical circular or cylindrical hull situated mainly below the water line places topside features right around the mean water line, where the largest wave impact loading is expected. The roll, heave, and pitching motion of such a hull shape and the curvature of the hull at the water surface may result in a different distribution of wave impact loading when compared to the expected loading on typical surface ship hull. Current studies have been conducted using traditional scale-model experiments complimented with computational fluid dynamic (CFD) methods to improve the predictions and the understanding of the contributing factors to the wave impact loading. The end goal is to try to validate CFD modeling methods for these submersible design cases to support the design process. The end products are design wave impact load requirements and ship operating guidance to help avoid damage due to wave impact load conditions.

Lessons Learned from Full-Scale Seakeeping Trial Acceleration Data for HighSpeed Planing Craft and Implications for Scale Model Testing

2017 ◽  
Author(s):  
Michael R. Riley ◽  
Timothy Coats
Keyword(s):  
High Speed ◽  
Impact Load ◽  
Maximum Load ◽  
Model Testing ◽  
Full Scale ◽  
Lessons Learned ◽  
Scale Model ◽  
Wave Impact ◽  
Acceleration Data ◽  
Hull Structure

This paper summarizes lessons learned from analyzing acceleration data recorded during full-scale seakeeping trials of high speed craft. Applications using a consistent maximum wave impact load approach in different areas of interest, including hull structure, shock isolation seat evaluation, and equipment ruggedness criteria are presented. The lessons learned and the maximum load applications suggest that there are implications for scale model testing and computational fluid dynamics.

Scale-model testing of reinforced concrete under impact loading conditions

1989 ◽  
Vol 16 (4) ◽  
pp. 459-466 ◽  
Author(s):  
J. A. Sato ◽  
F. J. Vecchio ◽  
H. M. Andre
Keyword(s):  
Reinforced Concrete ◽  
Key Words ◽  
Impact Loading ◽  
Impact Load ◽  
Scaling Theory ◽  
Scale Model ◽  
Reinforced Concrete Structures ◽  
Impact Loads ◽  
Test Program ◽  
Load Conditions

Aspects of scaling theory relating to the response of reinforced concrete structures under impact load conditions are reviewed. Details for modelling concrete and reinforcement, to be consistent with similitude requirements, are also discussed. A test program is described in which models of varying size were constructed, drop tested, and compared with prototype response. An analysis of the test data is made, indicating that, within certain limitations, the predictions of scaling theory are applicable to reinforced concrete subjected to extreme impact loads. Key words: cracking, impact, loads, modelling, reinforced concrete, scaling, stresses, structures, tests.

scholarly journals A Comprehensive Study of the Wave Impact Loads on an Inclined Plate

2019 ◽  
Vol 7 (4) ◽  
pp. 103 ◽  
Author(s):  
Ma ◽  
Zhou ◽  
Ren ◽  
Zhai
Keyword(s):  
Scale Model ◽  
Impact Loads ◽  
Ocean Engineering ◽  
Inclined Plate ◽  
Wave Impact ◽  
Uplift Force ◽  
Wave Slamming ◽  
Inclined Angle ◽  
Tremendous Impact ◽  
Good Agreement

Water wave impact on a wet deck is an important issue in ocean engineering, and the plate-shaped structure in the splash zone tends to suffer tremendous impact loads. This work presents a method for predicting the wave slamming uplift force on a fixed plate with different inclined angles. Both numerical simulation and the scale model test of the wave impact loads on an inclined plate were performed, and a good agreement was obtained. In addition, the influence of three important wave parameters on the slamming uplift force was systematically investigated: relative deck width B/LS, relative wave height Δh/H1/3, and the plate’s inclined angle α. The results indicate that the three parameters can significantly influence the wave slamming uplift force. Finally, a developed empirical equation is proposed for estimating the wave slamming uplift force on the inclined plate.

scholarly journals Multiphasic Study of Fluid-Dynamics and the Thermal Behavior of a Steel Ladle during Bottom Gas Injection Using the Eulerian Model

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1082
Author(s):  
Antonio Urióstegui-Hernández ◽  
Pedro Garnica-González ◽  
José Ángel Ramos-Banderas ◽  
Constantin Alberto Hernández-Bocanegra ◽  
Gildardo Solorio-Díaz
Keyword(s):  
Heat Exchange ◽  
Thermal Behavior ◽  
Gas Flow ◽  
Fluid Dynamic ◽  
Steel Slag ◽  
Scale Model ◽  
Discrete Ordinates ◽  
Transfer Model ◽  
Steel Ladle ◽  
Physical Scale

In this work, the fluid dynamic and thermal behavior of steel was analyzed during argon gas stirring in a 140-t refining ladle. The Eulerian multiphase mathematical model was used in conjunction with the discrete ordinates (DO) thermal radiation model in a steel-slag-argon system. The model was validated by particle image velocimetry (PIV) and the analysis of the opening of the oil layer in a physical scale model. The effect of Al2O3 and Mg-C as a refractory in the walls was studied, and the Ranz-Marshall and Tomiyama models were compared to determine the heat exchange coefficient. The results indicated that there were no significant differences between these heat exchange models; likewise, the radiation heat transfer model adequately simulated the thermal behavior according to plant measurements, finding a thermal homogenization time of the steel of 2.5 min for a gas flow of 0.45 Nm3·min−1. Finally, both types of refractory kept the temperature of the steel within the ranges recommended in the plant; however, the use of Al2O3 had better heat retention, which would favor refining operations.

scholarly journals EXTREME WAVE PRESSURES AND LOADS ON A PILE-SUPPORTED WHARF DECK - INFLUENCES OF AIR GAP AND WAVE DIRECTION

2018 ◽  
pp. 5
Author(s):  
Andrew Cornett
Keyword(s):  
Offshore Structures ◽  
Model Tests ◽  
Scale Model ◽  
Extreme Waves ◽  
Wave Direction ◽  
Coastal Structures ◽  
Extreme Wave ◽  
Wave Impact ◽  
The Past ◽  
Water Depths

Many deck-on-pile structures are located in shallow water depths at elevations low enough to be inundated by large waves during intense storms or tsunami. Many researchers have studied wave-in-deck loads over the past decade using a variety of theoretical, experimental, and numerical methods. Wave-in-deck loads on various pile supported coastal structures such as jetties, piers, wharves and bridges have been studied by Tirindelli et al. (2003), Cuomo et al. (2007, 2009), Murali et al. (2009), and Meng et al. (2010). All these authors analyzed data from scale model tests to investigate the pressures and loads on beam and deck elements subject to wave impact under various conditions. Wavein- deck loads on fixed offshore structures have been studied by Murray et al. (1997), Finnigan et al. (1997), Bea et al. (1999, 2001), Baarholm et al. (2004, 2009), and Raaij et al. (2007). These authors have studied both simplified and realistic deck structures using a mixture of theoretical analysis and model tests. Other researchers, including Kendon et al. (2010), Schellin et al. (2009), Lande et al. (2011) and Wemmenhove et al. (2011) have demonstrated that various CFD methods can be used to simulate the interaction of extreme waves with both simple and more realistic deck structures, and predict wave-in-deck pressures and loads.

Turbulence Modeling for Free-Surface Flow Simulations in Offshore Applications

2015 ◽  
Author(s):  
Henri J. L. van der Heiden ◽  
Arthur E. P. Veldman ◽  
Roel Luppes ◽  
Peter van der Plas ◽  
Joop Helder ◽  
...  
Keyword(s):  
Eddy Viscosity ◽  
Cfd Simulation ◽  
Turbulence Modeling ◽  
Free Surface Flow ◽  
Industrial Applications ◽  
Surface Flow ◽  
Absorbing Boundary Conditions ◽  
Wave Impact ◽  
Offshore Industry ◽  
Hydrodynamic Wave

To study extreme hydrodynamic wave impact in offshore and coastal engineering, the VOF-based CFD simulation tool ComFLOW is being developed. Recently, much attention has been paid to turbulence modeling, local grid refinement, wave propagation and absorbing boundary conditions. Here we will focus on the design of the turbulence model, which should be suitable for the coare grids as used in industrial applications. Thereto a blend of a QR-model and a regularization model has been designed, in combination with a dedicated wall model. The QR-model belongs to a class of modern eddy-viscosity models, where the amount of turbulent eddy viscosity is kept minimal. The performance of the model will be demonstrated with several applications relevant to the offshore industry. For validation, experiments have been carried out at MARIN.

An Assessment of Load and Response for Horizontal Slamming Loads From Model Scale Experiments

2018 ◽  
Author(s):  
Martin Storheim ◽  
Gunnar Lian
Keyword(s):  
Structural Response ◽  
Breaking Waves ◽  
Offshore Structures ◽  
Load Level ◽  
Material Behavior ◽  
Wave Impact ◽  
Large Variability ◽  
Slamming Load ◽  
Reasonable Approach ◽  
Wave Slamming

Steep breaking waves can result in high impact loads on offshore structures, and several model test campaigns have been conducted to assess the effect of horizontal wave slamming. High loads have been measured, and they can be challenging to withstand without significant deformation. For wave slamming problems it is common to estimate the characteristic slamming load and assume that this will give an equivalent characteristic response. One challenge related to the slamming load is that it has a large variability in load level, the duration of the load and the shape of the overall load pulse. This variability can have a large impact on the estimated response to the characteristic load, causing a similar or larger variability in response. Due to the sensitivity to the structural response, it may be difficult to interpret large amounts of such data to arrive at a relevant design load without making overly conservative assumptions. This paper investigates the sensitivity of the structural response to assumptions made in the material modelling and how the short term variability is affected if we instead of load use response indicators such as plastic strain and max deformation to arrive at a characteristic load. For this purpose, a simplified dynamic response model is created, and the recorded wave impact events can then be evaluated based on the predicted structural response from the simplified model. It was found that the structural response is sensitive to the structural configuration. The assumed material behavior and hydro-elastoplastic effects were identified to greatly affect the structural response. A reasonable approach to arrive at the q-annual response seems to be to first estimate the q-annual extreme slamming load, and then run the structural analysis on several of the measured slamming time series with the estimated q-annual extreme pressure.

CFD Modeling of Thermal Management Systems for a Silicon Semiconductor Switch

2020 ◽  
Author(s):  
Jordan N. Berg ◽  
Sarvenaz Sobhansarbandi
Keyword(s):  
Thermal Management ◽  
Fluid Dynamic ◽  
Jet Impingement ◽  
Liquid System ◽  
Pulse Power ◽  
Cfd Modeling ◽  
Inlet Temperature ◽  
Ansys Fluent ◽  
Term Operation ◽  
Semiconductor Switches

Abstract Silicon semiconductor switches are suitable for pulse power applications. When utilized in these applications, the switch receives a significant amount of power (i.e., heat) that is to be dissipated, which can result in the degradation of the switch. In order to maintain the functionality of the switch, a thermal management system (TMS) needs to be developed to keep the switch temperature at no higher than 80 °C during operation. This threshold is set due to an increase in electrical resistivity of silicon with an increase in temperature. This study compares the viability of two TMS, a microchannel and a jet impingement single-phase liquid system, to facilitate the long term operation of the switch for pulse power applications through performing computational fluid dynamic modeling (CFD) in ANSYS Fluent. The results from this study show that by utilizing a jet impingement system as TMS, the temperature of switch is maintained below the desired operating temperature when compared to that of the microchannel design under identical operating parameters (i.e., mass flow rate, coolant type and inlet temperature). Moreover, a cross validation of the thermal performance of the proposed systems has been made to further validate the obtained results.

Wave Impact Load and Corresponding Nonlinear Response of a Semi-Submersible

2019 ◽  
Author(s):  
Yinghao Guo ◽  
Longfei Xiao ◽  
Handi Wei ◽  
Lei Li ◽  
Yanfei Deng
Keyword(s):  
Spatial Distribution ◽  
Structural Integrity ◽  
Impact Load ◽  
Wave Crest ◽  
Impulsive Effect ◽  
Offshore Platforms ◽  
Wave Impact ◽  
Global Response ◽  
Local Wave ◽  
Incident Waves

Abstract Offshore platforms operating in harsh ocean environments often suffer from severe wave impacts which threaten the structural integrity and staffs safety. An experimental study was carried out to investigate the wave impact load and its effect on the global response of a semi-submersible. First, two typical wave impact events occurring successively in the wave test run are analyzed, including the characteristics of incident waves, relative wave elevations and the spatial distribution of the wave impact load. Subsequently, the corresponding global response of the semi-submersible under these two wave impacts are investigated in time domain. It reveals that compared with the incident wave, the relative wave elevation has a more straightforward relationship with the wave impact load. The relative wave crest height is associated with the spatial distribution of the wave impact load, while the local wave steepness matters more in the magnitude of the wave impact load. The impulsive effect of the wave impact load on the motion behaviors is not obvious. But severe wave impacts can introduce excessive horizontal accelerations and nonlinear behaviors like ringing in the acceleration response.

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