scholarly journals CFD investigation of interaction effect between hull and accommodation on wind drag of a container ship in head wind

2021 ◽  
Vol 21 (1) ◽  
pp. 37-46
Author(s):  
He Ngo Van ◽  
Thuan Truong Van

In this paper, we present a research on applying a commercial Computational Fluid Dynamics (CFD) code to determine interaction effect between hull and accommodation on wind drag of a container ship. For the high superstructure and large windward area ships such as container, wind drag acting on hull accounts for a large amount of total resistance. To clearly find aerodynamic performance and interaction effects on wind drag of a container ship, a full scale 1,200 TEU container has been used as a reference model. From results of comparison in the two computed cases of hull with and without accommodation, the interaction effects between hull and accommodation on aerodynamic performance and wind drag have been investigated. The targets of the paper has proposed a new solution to improve aerodynamic performances and reduce wind drag acting on the ship by reducing interaction effects between hull and accommodation.

2020 ◽  
Vol 8 (11) ◽  
pp. 930
Author(s):  
Ngo Van He ◽  
Ngo Van Hien ◽  
Van-Thuan Truong ◽  
Ngoc-Tam Bui

In this paper, we present our research on applying the commercial Computational Fluid Dynamics (CFD) code to investigate interaction effect between hull and accommodation on wind drag acting above the water hull surface of a full scale 1200 TEU container ship. With this purpose, aerodynamic performances and wind drag acting on the ship hull with and without accommodations have been computed. Analyzing the obtained CFD results, the interaction effect between hull and accommodation on aerodynamic performances and wind drag acting on the ship have been found. Various new accommodation shapes have been proposed for the original ship to reduce the interaction effect on wind drag. A drastic reduction in the interaction effect between hull and accommodation on wind drag acting on the ship has been achieved and the obtained results have been shown in this paper.


2019 ◽  
Vol 18 (4) ◽  
pp. 413-421
Author(s):  
Ninh Cong Toan ◽  
Ngo Van He

In marine transportation, aerodynamic performance is important for the ships, especially for the small passenger fast ships. It has affected the service speed, air resistance acting on hull, power energy as well as roll, pitch, yaw and stability of the ships. Moreover, the aerodynamic performance also directly affects the passengers, captains or employments who work on the ships. For a bad aerodynamic performance hull shape, it may make an accident in marine transportation. In this paper, the authors present a study on effect of hull shape on aerodynamic performance of a small passenger fast ship by using a commercial Computational Fluid Dynamics (CFD). Several hull forms with different shapes are proposed and computed to show their aerodynamic performances. From the comparison between different CFD results of the ships, the effects of hull shape on aerodynamic performances of the ships  are understood.


Author(s):  
Baojie Liu ◽  
Jiaxin Liu ◽  
Xianjun Yu ◽  
Dejun Meng ◽  
Wenbin Shi

Abstract The results of previous studies have proved that manufacture variations can cause a noticeable influence on compressor aerodynamic performance. The main objective of this paper is to investigate the influence rules and mechanisms of manufacture variations on supersonic/transonic blades aerodynamic performance. The variations used in this study were measured from some newly manufactured high-pressure compressors. In the present study, several blade sections with different design Mach number conditions are selected for further statistical analysis of measured deviation data. Therefore, some systematic errors in the deviation data have been revealed. Based on these data, the computational fluid dynamics (CFD) method has been used to obtain the aerodynamic performances of a large number of the measured blade elements. And then, the analysis of the influence rules of manufacture variations on blade aerodynamic performance in different Mach number conditions has been carried out. The present results indicate that the effects of manufacture variations on blade aerodynamic performance in the lower Mach number (0.8) condition are much more significant comparing to that in the higher Mach number (0.9∼1.2) conditions. Based on this, influence mechanisms of manufacture variations on positive incidence range and negative incidence range have been analyzed. The differences of influence mechanisms in different Mach number conditions are the focus of research.


2018 ◽  
Vol 7 (4.13) ◽  
pp. 202-204
Author(s):  
Mahadhir A Rahman ◽  
Mohammad Yazdi Harmin ◽  
Mohd Fuad Koslan ◽  
Mohd Rashdan Saad ◽  
Mohd Faisal Abdul Hamid

This paper presents the investigation of aerodynamic performance of inboard Store-X and Store-Y configurations on the X-plane aircraft model through computational fluid dynamics (CFD) analysis. The X-plane and Store-Y represent the default store and pylon integration while Store-X provides a possibility for other types of store to be integrated. These stores are loosely based upon the two most commonly used by the western and eastern blocks. The resultant lift, drag and moment forces are of interest in order to observe their impact with respect to the two different stores configurations. The finding shows that the aerodynamic impact with respect to Store-X installation on the inboard pylon station is insignificant when compared to default system, hence offers the safety of delivering the Store-X from the X-plane aircraft.


2019 ◽  
Vol 19 (3) ◽  
pp. 345-447
Author(s):  
Luong Ngoc Loi ◽  
Nguyen Chi Cong ◽  
Ngo Van He

In this work, the commercial Computational Fluid Dynamics (CFD), ANSYS-Fluent V.14.5 has been used to illustrate the effects of rudder and blade pitch on hydrodynamic performances of a propeller. At first, the characteristic curves of a container ship propeller are computed. Then, effects of rudder on hydrodynamic performances of the propeller in the both cases of the propeller with and without rudder have been investigated. The relationships between the blade pitch angle and the hydrodynamic performances of the selected referent propeller in this work having designed conditions as diameter of 3.65 m; speed of 200 rpm; average pitch of 2.459 m and the boss ratio of 0.1730. Using CFD, the characteristic curves of the marine propeller, pressure distribution, velocity distribution around propeller and the efficiency of the propeller have been shown. From the obtained results, the effects of rudder and blade pitch angle on hydrodynamic performances of the propeller have been evaluated.


Author(s):  
Emil Shivachev ◽  
Mahdi Khorasanchi ◽  
Alexander H. Day

There has been a lot of interest in trim optimisation to reduce fuel consumption and emissions of ships. Many existing ships are designed for a single operational condition with the aim of producing low resistance at their design speed and draft with an even keel. Given that a ship will often sail outside this condition over its operational life and moreover some vessels such as LNG carriers return in ballast condition in one leg, the effect of trim on ships resistance will be significant. Ship trim optimization analysis has traditionally been done through towing tank testing. Computational techniques have become increasingly popular for design and optimization applications in all engineering disciplines. Computational Fluid Dynamics (CFD), is the fastest developing area in marine fluid dynamics as an alternative to model tests. High fidelity CFD methods are capable of modelling breaking waves which is especially crucial for trim optimisation studies where the bulbous bow partially emerges or the transom stern partially immerses. This paper presents a trim optimization study on the Kriso Container Ship (KCS) using computational fluid dynamics (CFD) in conjunction with towing tank tests. A series of resistance tests for various trim angles and speeds were conducted at 1:75 scale at design draft. CFD computations were carried out for the same conditions with the hull both fixed and free to sink and trim. Dynamic sinkage and trim add to the computational cost and thus slow the optimisation process. The results obtained from CFD simulations were in good agreement with the experiments. After validating the applicability of the computational model, the same mesh, boundary conditions and solution techniques were used to obtain resistance values for different trim conditions at different Froude numbers. Both the fixed and free trim/sinkage models could predict the trend of resistance with variation of trim angles; however the fixed model failed to measure the absolute values as accurately as the free model. It was concluded that a fixed CFD model, although computationally faster and cheaper, can find the optimum trim angle but cannot predict the amount of savings with very high accuracy. Results concerning the performance of the vessel at different speeds and trim angles were analysed and optimum trim is suggested.


Author(s):  
T. Batuhan Korkut ◽  
Aytac Goren

This study focuses on the aerodynamic performances of two vehicles by Dokuz Eylul University Solaris Solar Car Project Team. The first vehicle (S7) is a solar-powered vehicle that is designed for World Solar Challenge and the second (D9) is an electric vehicle which is designed for Tubitak EV Challenge. Both vehicles are manufactured using polymer composites and challenged in mentioned races. In this research, a formal optimisation technique based on computational fluid dynamics (CFD) is used to determine the efficient aerodynamic structures under various scenarios. Results clearly show that strategists of the racing teams should take intoaccount the aerodynamic structure of the racing car. Especially before the races which based on efficiency, the apex line is determined, and mirrors should be replaced by back view camera.


2021 ◽  
Vol 11 (5) ◽  
pp. 7665-7672
Author(s):  
D. Bhatia ◽  
Y. Zhao ◽  
D. Yadav ◽  
J. Wang

This paper explores the use of sharkskin in improving the aerodynamic performance of aerofoils. A biomimetic analysis of the sharkskin denticles was conducted and the denticles were incorporated on the surface of a 2-Dimensional (2D) NACA0012 aerofoil. The aerodynamic performance including the drag reduction rate, lift enhancement rate, and Lift to Drag (L/D) enhancement rate for sharkskin denticles were calculated at different locations along the chord line of the aerofoil and at different Angles of Attack (AOAs) through Computational Fluid Dynamics (CFD). Two different denticle orientations were tested. Conditional results indicate that the denticle reduces drag by 4.3% and attains an L/D enhancement ratio of 3.6%.


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