Prediction of wave resistance by a Reynolds-averaged Navier–Stokes equation–based computational fluid dynamics approach

Kınacı, Ömer Kemal; Sukas, Ömer Faruk; Bal, Şakir

doi:10.1177/1475090215599180

Cited by 6 publications

(6 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Simulations were performed using the standard k-ε model (Jones and Launder, 1972) in two-layer formulation (Rodi, 1991). While there are limitations associated with the k-ε turbulence model (Lloyd and Espanoles, 2002), this model results in a significant reduction of computational time, and examples in the literature have demonstrated that the k-ε model turbulence mode provides accurate results for geometries and flow conditions comparable to those presented in this work (Sridhar et al, 2010;Kinaci et al, 2015). Further, we were interested in relative differences between the forces created by a range of tag geometries and not absolute estimates of force, a question that lends itself well to an efficient computational approach.…”

Section: Computational Fluid Dynamics Simulationsmentioning

confidence: 83%

Swimming Energy Economy in Bottlenose Dolphins Under Variable Drag Loading

Hoop

Fahlman²,

Shorter

et al. 2018

Front. Mar. Sci.

View full text Add to dashboard Cite

Instrumenting animals with tags contributes additional resistive forces (weight, buoyancy, lift, and drag) that may result in increased energetic costs; however, additional metabolic expense can be moderated by adjusting behavior to maintain power output. We sought to increase hydrodynamic drag for near-surface swimming bottlenose dolphins, to investigate the metabolic effect of instrumentation. In this experiment, we investigate whether (1) metabolic rate increases systematically with hydrodynamic drag loading from tags of different sizes or (2) whether tagged individuals modulate speed, swimming distance, and/or fluking motions under increased drag loading. We detected no significant difference in oxygen consumption rates when four male dolphins performed a repeated swimming task, but measured swimming speeds that were 34% (>1 m s −1) slower in the highest drag condition. To further investigate this observed response, we incrementally decreased and then increased drag in six loading conditions. When drag was reduced, dolphins increased swimming speed (+1.4 m s −1 ; +45%) and fluking frequency (+0.28 Hz; +16%). As drag was increased, swimming speed (−0.96 m s −1 ; −23%) and fluking frequency (−14 Hz; 7%) decreased again. Results from computational fluid dynamics simulations indicate that the experimentally observed changes in swimming speed would have maintained the level of external drag forces experienced by the animals. Together, these results indicate that dolphins may adjust swimming speed to modulate the drag force opposing their motion during swimming, adapting their behavior to maintain a level of energy economy during locomotion.

show abstract

Section: Computational Fluid Dynamics Simulationsmentioning

confidence: 83%

Swimming Energy Economy in Bottlenose Dolphins Under Variable Drag Loading

Hoop

Fahlman²,

Shorter

et al. 2018

Front. Mar. Sci.

View full text Add to dashboard Cite

show abstract

“…and (1+k) are assumed constant with scale, while is predicted via a friction line (Molland et al, 2017). Since CFD cannot be used to predict all of these components via a multiphase simulation, one may replace the free-surface with a symmetry plane (Kinaci et al, 2016). Essentially, this is equivalent to removing from Eq.…”

Section: Reynolds-averaged Navier-stokesmentioning

confidence: 99%

Numerical and experimental study on hydrodynamic performance of ships advancing through different canals

et al. 2020

View full text Add to dashboard Cite

In international shipping, there are several waterways that are widely viewed as bottlenecks. Among these is the Suez Canal, where recent expansions have taken place. Although the Suez Canal has a high importance in international shipping, little research has been carried out in maximising the number of ships capable of traversing for a set period of time. The present study aims to examine hydrodynamic phenomena of ships advancing through the Suez Canal in the allowed speed range to determine the relative effects of the canal depth and /or width restrictions on the overall ship sailing performance. A rectangular canal is also included as a reference to gauge the effects of varying canal cross-section. The present study combines experimental, numerical, analytical and empirical methods for a holistic approach in calm water. As a case-study, the KCS hullform is adopted, and analysed experimentally, via Computational Fluid Dynamics, using the slender body theory, and empirical formulae. The results reveal strong coupling between the canal's cross section and all examined parameters.

show abstract

“…29,30 Therefore, by performing numerical FSS and DBS, every resistance component can be assessed. Furthermore, as it was lately proven that form factor value is dependent on Reynolds number, 28 computational fluid dynamics (CFD) based on the viscous flow can be used for the improvement of reliability of extrapolation methods, as well as for the reduction of the incremental resistance coefficient. 31 In addition, with the application of the roughness functions for biofilm, the determination of the effect of biofilm on each resistance component is enabled.…”

Section: Resistance Characteristicsmentioning

confidence: 99%

“…Since a body which is fully submerged within a fluid of infinite depth has no wave resistance, C VP can be determined using double body simulation (DBS) by integrating the pressure over the immersed hull surface. 28 In addition, form factor values can be obtained as follows…”

Section: Governing Equationsmentioning

confidence: 99%

Impact of biofilm on the resistance characteristics and nominal wake

Farkas

Degiuli

Martić

2019

Proceedings of the Institution of Mechanical Engineers, Part M:

View full text Add to dashboard Cite

Numerical assessment of the impact of biofilm on the resistance characteristics and nominal wake is carried out within this study. Therefore, roughness function models are implemented within the wall function of the commercial software package. Extensive verification study as well as the estimation of numerical uncertainties in the prediction of the resistance characteristics and nominal wake is made. Furthermore, numerical uncertainties in the prediction of the change in resistance characteristics and nominal wake are assessed as well. Thereafter, validation study is carried out by comparing the obtained increases in the frictional and total resistance with the increases obtained using Granville similarity law scaling method. The significant impact of biofilm on the resistance characteristics as well as on the nominal wake is noted. Thus, total resistance and frictional resistance increase due to the presence of biofilm, while wave resistance decreases, contradicting the classical methods, which consider that only frictional resistance is affected due to the presence of roughness. Furthermore, nominal wake coefficient is increased due to the presence of biofilm, which causes slowdown of the flow.

show abstract

Prediction of wave resistance by a Reynolds-averaged Navier–Stokes equation–based computational fluid dynamics approach

Cited by 6 publications

References 43 publications

Swimming Energy Economy in Bottlenose Dolphins Under Variable Drag Loading

Swimming Energy Economy in Bottlenose Dolphins Under Variable Drag Loading

Numerical and experimental study on hydrodynamic performance of ships advancing through different canals

Impact of biofilm on the resistance characteristics and nominal wake

Contact Info

Product

Resources

About