Numerical study on the hydrodynamic drag force of a container ship model

Elkafas, Ahmed G.; Elgohary, Mohamed M.; Zeid, Akram

doi:10.1016/j.aej.2019.07.004

Cited by 35 publications

(10 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It can, therefore, be concluded that the drag force and offset angle in the Y-direction were more easily affected by centripetal forces in the stopping state. The relationship between the average drag coefficient (C d ), the average drag force (F), the wetted area (A), and drag velocity (U) is given by [19]:…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Experimental and Numerical Model Investigations of the Underwater Towing of a Subsea Module

Zan

Guo

Yuan

et al. 2019

JMSE

View full text Add to dashboard Cite

In underwater towing operations, the drag force and vertical offset angle of towropes are important considerations when choosing and setting up towing equipment. The aim of this paper is to study the variation in drag force, vertical offset angle, resistance, and attitude for towing operations with a view to optimizing these operations. An underwater experiment was conducted using a 1:8 scale physical model of a subsea module. A comprehensive series of viscous Computational Fluid Dynamics (CFD) simulations were carried out based on Reynolds-averaged Navier–Stokes equations for uniform velocity towing. The results of the simulation were compared with experimental data and showed good agreement. Numerical results of the vorticity field and streamlines at the towing speeds were presented to analyze the distribution of vortexes and flow patterns. The resistance components were analyzed based on the numerical result. It was found that the lateral direction was a better direction for towing operations because of the smaller drag force, resistance, and offset angle. Similar patterns and locations of streamlines and vortexes were present in both the longitudinal and lateral directions, the total resistance coefficient decreases at a Reynolds number greater than that of a cylinder.

show abstract

Section: Resultsmentioning

confidence: 99%

“…The RANS method calculates the hydrodynamic drag using an integral over the wetted surface [26]. The frictional, pressure and total resistance coefficients are calculated as follows [19]:…”

Section: Resistance Component Analysismentioning

confidence: 99%

Experimental and Numerical Model Investigations of the Underwater Towing of a Subsea Module

Zan

Guo

Yuan

et al. 2019

JMSE

View full text Add to dashboard Cite

show abstract

“…Where Where, (GT) is the gross tonnage of passenger ship, (X) is the reduction rate set by IMO as follow; 5% in phase 1 (2015-2019), 20% in phase 2 (2020-2024) and 30% in phase 3 (2025-onwards) (El Gohary and Ammar 2016; Elkafas et al 2019).…”

Section: Performance Evaluation Methodologymentioning

confidence: 99%

Investigation of ship electric propulsion system performance from environmental and energy efficiency perspective

Elkafas

Shouman

2021

Preprint

Self Cite

View full text Add to dashboard Cite

The maritime industry faces many challenges regarding the adverse environmental impact, whether at the level of legislation set by the International Maritime Organization (IMO) or the economic crises that arising from the Covid-19 pandemic. IMO has found that the highest percentage of ship emission is mainly coming from the ship propulsion systems. Therefore, the current research proposes an electric propulsion system to drive the ship instead of the conventional one to reduce ship emissions and enhance energy efficiency. As a case study, a passenger ship is investigated. The results showed that the proposed electric propulsion system has lower emission rates than the conventional one by 10%, 21%, and 88% for CO2, NOx, and SOx emission, respectively. From an energy efficiency point of view, the diesel-electric propulsion system enhances the energy efficiency and complies with the required IMO values as actual energy efficiency is about 66%, 70%, 83%, and 95% of the required IMO values at baseline, phase 1, phase 2 and phase 3, respectively.

show abstract

“…The most recommended computational domain at the velocity inlet was set at 1.5L forward perpendicular to the front and at the outlet pressure was 3.5L towards the back which was measured perpendicularly. To eliminate the effect of backward viscous pressure on the side boundaries, the transverse and vertical directions were set at 1.5L (Elkafas et al, 2019), as shown in Figure 2. The downstream boundary condition was determined as pressure outflow by adjusting the static pressure to prevent reverse flow (Ford and Winroth, 2019).…”

Section: Computational Domainmentioning

confidence: 99%

Numerical Investigation into the Pressure and Flow Velocity Distributions of a Slender-Body Catamaran Due to Viscous Interference Effects

Utama¹,

Aryawan²,

Nasirudin³

et al. 2021

IJTech

View full text Add to dashboard Cite

A computational fluid dynamics investigation was carried out on a slender body catamaran to determine the effect of pressure and flow velocity changes for varied hull separations. The investigation was conducted using an NPL 4a model with a slenderness (length to breadth) ratio of about 11 together with the use of a commercial code (CFX) with hull separations of S/L = 0.3 and 0.4 along with a variation in Reynolds numbers of 2.86×105, 3.43×105, 4.01×105, and 4.44×105. Pressure and flow velocity around the hull were measured to obtain a fluid effect attributed to the influence of catamaran hull interference. A computational fluid dynamics investigation was carried out with the same configurations as those in the experimental tests. The overall results were in good agreement, with the order of discrepancy at about 1.76%; the computational fluid dynamics results were consistently lower than the experimental ones. Both tests demonstrated a viscous interaction between the hulls and, thus, the form factors for the demihull and catamaran were properly derived: the form factor for the demihull (1+k) was 1.254 and for the catamaran (1+βk) was 1.420, indicating interaction effects of about 13.2%. The form factor for the catamaran was consistently higher than the demihull, suggesting some viscous interference between the hulls. The effect of catamaran hull interference variation can be recognized through the velocity augmentation ratio (σ), pressure change ratio (ϕ), and the viscous interference factor (β). In addition, the β value is very helpful for finding out the interference of the hull on a catamaran when sophisticated experimental and numerical tools are not available.

show abstract

Numerical study on the hydrodynamic drag force of a container ship model

Cited by 35 publications

References 15 publications

Experimental and Numerical Model Investigations of the Underwater Towing of a Subsea Module

Experimental and Numerical Model Investigations of the Underwater Towing of a Subsea Module

Investigation of ship electric propulsion system performance from environmental and energy efficiency perspective

Numerical Investigation into the Pressure and Flow Velocity Distributions of a Slender-Body Catamaran Due to Viscous Interference Effects

Contact Info

Product

Resources

About