Laboni Afroz | Bangladesh University of Engineering & Technology (original) (raw)

Papers by Laboni Afroz

Research paper thumbnail of An Experiment with a Ship Model for Prediction of Added Resistance in Waves

Procedia Engineering, 2017

An experiment was carried out with a ship model for prediction of added resistance in waves in th... more An experiment was carried out with a ship model for prediction of added resistance in waves in the Flume of the Department of Water Resources Engineering of BUET. The flume has the dimension of 21.34 m x 0.762 m x 0.762 m, with wave generation facility at one end and an absorber at the other end. The overall length, breadth and depth of the ship model are 1 m, 0.213 m and 0.083 m respectively. The experiment was carried out in waves at different wavelengths and heights as well as in calm water at different speeds. The added resistance was determined by subtracting calm water resistance from the total resistance obtained in waves applying constant speed approach. The added resistance so obtained was expressed in non-dimensional form. The experimental results were compared with the theoretical ones obtained for the same ship model applying computer programs developed for ship added resistance in waves.

Research paper thumbnail of Seakeeping Performance OF Series 60 Ships

The seakeeping performance in terms of added resistance in head and oblique seas of five series 6... more The seakeeping performance in terms of added resistance in head and oblique seas of five series 60 ships, parent form, have been evaluated analytically. The results are presented in tabular forms as function of principal particulars of ship, Froude Number, wave heading and the seaway. Some comparisons of the results obtained analytically have been made with that obtained from seakeeping tables of Grigoropoulos et. al. [2].

Research paper thumbnail of Added Resistance in Waves, Notably in Short Waves

Research paper thumbnail of Effect of waves on added resistance of ships

Numerical prediction of added resistance of a ship in waves has always been the most difficult an... more Numerical prediction of added resistance of a ship in waves has always been the most difficult and challenging task for Naval Architects. Researchers are continuously making efforts for better prediction of added resistance of ships in waves. Unfortunately none of the existing methods available for determining the added resistance of ships in waves are convincingly accurate, in particular over the range of wavelengths which are short compared to the length of a ship. In this thesis a method for prediction of added resistance due to short waves, which is attributed as added resistance due to wave reflection has been proposed by the Author and a computer code has also been developed based on the proposed method. The total added resistance is obtained by adding the added resistance due ship motion by Maruo’s method with that of added resistance due to wave reflection by Author’s method. The computations are made for series 60 ships, parent form, SR108 container ship and KVLCC2 and the ...

Research paper thumbnail of Estimation of linear hydrodynamic derivatives of a VLCC using static drift simulation

Prediction of ship hydrodynamic derivatives is essential to evaluate ship’s maneuvering capabilit... more Prediction of ship hydrodynamic derivatives is essential to evaluate ship’s maneuvering capabilities. In this paper, static drift simulation results are shown for a very large crude carrier ship model, KVLCC2. For simulation, a RaNS based solver, SHIP_Motion, was used. The solver solves overset structured mesh using finite volume method. The simulation results were compared with experimental data. Next, linear hydrodynamic derivatives were predicted from simulation results and compared with experimental ones. The results show good agreement with experimental data and the paper concludes that the solver, SHIP_ Motion, is well capable to estimate hydrodynamic derivatives maintaining reasonable accuracy and economics.

Research paper thumbnail of An Experiment with a Ship Model for Prediction of Added Resistance in Waves

Procedia Engineering, 2017

An experiment was carried out with a ship model for prediction of added resistance in waves in th... more An experiment was carried out with a ship model for prediction of added resistance in waves in the Flume of the Department of Water Resources Engineering of BUET. The flume has the dimension of 21.34 m x 0.762 m x 0.762 m, with wave generation facility at one end and an absorber at the other end. The overall length, breadth and depth of the ship model are 1 m, 0.213 m and 0.083 m respectively. The experiment was carried out in waves at different wavelengths and heights as well as in calm water at different speeds. The added resistance was determined by subtracting calm water resistance from the total resistance obtained in waves applying constant speed approach. The added resistance so obtained was expressed in non-dimensional form. The experimental results were compared with the theoretical ones obtained for the same ship model applying computer programs developed for ship added resistance in waves.

Research paper thumbnail of Seakeeping Performance of Series 60 Ships

Procedia Engineering, 2017

The seakeeping performance in terms of added resistance in head and oblique seas of five series 6... more The seakeeping performance in terms of added resistance in head and oblique seas of five series 60 ships, parent form, have been evaluated analytically. The results are presented in tabular forms as function of principal particulars of ship, Froude Number, wave heading and the seaway. Some comparisons of the results obtained analytically have been made with that obtained from seakeeping tables of Grigoropoulos et. al. [2].

Research paper thumbnail of Computational analysis of asymmetric water entry of wedge and ship section at constant velocity

AIP Conference Proceedings, 2016

Water impact problems receive much attention due to their short duration and large unsteady compo... more Water impact problems receive much attention due to their short duration and large unsteady component of hydrodynamic loads. The effect of water entry has several important applications in various aspects of the naval field. Significant attention has been given to various water entry phenomena such as ship slamming, planning hulls, high-speed hydrodynamics of seaplanes, surface-piercing propellers and the interaction of high-speed liquid drops with structural elements. Asymmetric water entry may be caused by various natural phenomena such as weather conditions or strong winds. Since the determination of hydrodynamic impact load plays a vital role in designing safe and effcient vessels, an accurate and reliable prediction method is necessary to investigate asymmetric water entry problems. In this paper, water entry of a two-dimensional wedge and ship section at constant velocity in asymmetric condition will be analysed numerically and the effects of asymmetric impact on the velocity and pressure distributi...

Research paper thumbnail of Study on the Development of Water Transport Network for Passengers in the Gulshan-Banani-HatirJheel Lake of the Capital City of Bangladesh

Journal of Shipping and Ocean Engineering, 2015

Dhaka, the capital city of Bangladesh is one of the most overpopulated city in the world and traf... more Dhaka, the capital city of Bangladesh is one of the most overpopulated city in the world and traffic jam is the most severe and regular affliction in the daily life. Also, the existing vehicles are not sufficient in compared to the population of the city. People have to spend many hours simply sitting in the traffic jam. This lessens the productivity of people and brings sufferings to them. Gulshan-Banani-HatirJheel area is the busiest regions within the city and face severe traffic jam during working hours. These lakes are totally unused. Therefore, there is a possibility to build a waterways network for passengers transport through these lakes. This will reduce the affliction of people via reducing traffic jam. The proposed transportation networks will also preserve the natural environment of the lakes and bring a source of entertainment in the city life. Many developed cities in the world like London, New York, Paris, Venice, Shanghai etc. already have implemented waterways network inside the city and successfully made the best use of cistern side.

Research paper thumbnail of Comparative Study of RaNS and PF based Solver for Predicting Added Resistance of a Very Large Crude Carrier

Procedia Engineering, 2017

Computational ship hydrodynamics has gained high popularity in shipbuilding industry in recent ye... more Computational ship hydrodynamics has gained high popularity in shipbuilding industry in recent years because of its high efficiency and improved accuracy. Reliable performance prediction at design stage is essential for large structures, like ships, to ensure design conformance and buyer 's acceptance. Thus, shipbuilders are emphasizing and relying more and more on computational methods. This paper aims at providing a comparative study of added resistance and related motion prediction using a Reynolds averaged Navier-Stokes (RaNS) and potential flow (PF) based solver, for a very large crude career, KVLCC2. The used RaNS solver, SHIP Motion, solves overset structured mesh using finite volume method. The PF solver is a commercial solver named HydroSTAR that uses 3D panel method for simulation and prediction. The paper compares both the results and shows that the RaNS solver is better in predicting added resistance, however, in case of motion predicting, both show similar level of accuracy.

Research paper thumbnail of An Experiment with a Ship Model for Prediction of Added Resistance in Waves

Procedia Engineering, 2017

An experiment was carried out with a ship model for prediction of added resistance in waves in th... more An experiment was carried out with a ship model for prediction of added resistance in waves in the Flume of the Department of Water Resources Engineering of BUET. The flume has the dimension of 21.34 m x 0.762 m x 0.762 m, with wave generation facility at one end and an absorber at the other end. The overall length, breadth and depth of the ship model are 1 m, 0.213 m and 0.083 m respectively. The experiment was carried out in waves at different wavelengths and heights as well as in calm water at different speeds. The added resistance was determined by subtracting calm water resistance from the total resistance obtained in waves applying constant speed approach. The added resistance so obtained was expressed in non-dimensional form. The experimental results were compared with the theoretical ones obtained for the same ship model applying computer programs developed for ship added resistance in waves.

Research paper thumbnail of Seakeeping Performance OF Series 60 Ships

The seakeeping performance in terms of added resistance in head and oblique seas of five series 6... more The seakeeping performance in terms of added resistance in head and oblique seas of five series 60 ships, parent form, have been evaluated analytically. The results are presented in tabular forms as function of principal particulars of ship, Froude Number, wave heading and the seaway. Some comparisons of the results obtained analytically have been made with that obtained from seakeeping tables of Grigoropoulos et. al. [2].

Research paper thumbnail of Added Resistance in Waves, Notably in Short Waves

Research paper thumbnail of Effect of waves on added resistance of ships

Numerical prediction of added resistance of a ship in waves has always been the most difficult an... more Numerical prediction of added resistance of a ship in waves has always been the most difficult and challenging task for Naval Architects. Researchers are continuously making efforts for better prediction of added resistance of ships in waves. Unfortunately none of the existing methods available for determining the added resistance of ships in waves are convincingly accurate, in particular over the range of wavelengths which are short compared to the length of a ship. In this thesis a method for prediction of added resistance due to short waves, which is attributed as added resistance due to wave reflection has been proposed by the Author and a computer code has also been developed based on the proposed method. The total added resistance is obtained by adding the added resistance due ship motion by Maruo’s method with that of added resistance due to wave reflection by Author’s method. The computations are made for series 60 ships, parent form, SR108 container ship and KVLCC2 and the ...

Research paper thumbnail of Estimation of linear hydrodynamic derivatives of a VLCC using static drift simulation

Prediction of ship hydrodynamic derivatives is essential to evaluate ship’s maneuvering capabilit... more Prediction of ship hydrodynamic derivatives is essential to evaluate ship’s maneuvering capabilities. In this paper, static drift simulation results are shown for a very large crude carrier ship model, KVLCC2. For simulation, a RaNS based solver, SHIP_Motion, was used. The solver solves overset structured mesh using finite volume method. The simulation results were compared with experimental data. Next, linear hydrodynamic derivatives were predicted from simulation results and compared with experimental ones. The results show good agreement with experimental data and the paper concludes that the solver, SHIP_ Motion, is well capable to estimate hydrodynamic derivatives maintaining reasonable accuracy and economics.

Research paper thumbnail of An Experiment with a Ship Model for Prediction of Added Resistance in Waves

Procedia Engineering, 2017

An experiment was carried out with a ship model for prediction of added resistance in waves in th... more An experiment was carried out with a ship model for prediction of added resistance in waves in the Flume of the Department of Water Resources Engineering of BUET. The flume has the dimension of 21.34 m x 0.762 m x 0.762 m, with wave generation facility at one end and an absorber at the other end. The overall length, breadth and depth of the ship model are 1 m, 0.213 m and 0.083 m respectively. The experiment was carried out in waves at different wavelengths and heights as well as in calm water at different speeds. The added resistance was determined by subtracting calm water resistance from the total resistance obtained in waves applying constant speed approach. The added resistance so obtained was expressed in non-dimensional form. The experimental results were compared with the theoretical ones obtained for the same ship model applying computer programs developed for ship added resistance in waves.

Research paper thumbnail of Seakeeping Performance of Series 60 Ships

Procedia Engineering, 2017

The seakeeping performance in terms of added resistance in head and oblique seas of five series 6... more The seakeeping performance in terms of added resistance in head and oblique seas of five series 60 ships, parent form, have been evaluated analytically. The results are presented in tabular forms as function of principal particulars of ship, Froude Number, wave heading and the seaway. Some comparisons of the results obtained analytically have been made with that obtained from seakeeping tables of Grigoropoulos et. al. [2].

Research paper thumbnail of Computational analysis of asymmetric water entry of wedge and ship section at constant velocity

AIP Conference Proceedings, 2016

Water impact problems receive much attention due to their short duration and large unsteady compo... more Water impact problems receive much attention due to their short duration and large unsteady component of hydrodynamic loads. The effect of water entry has several important applications in various aspects of the naval field. Significant attention has been given to various water entry phenomena such as ship slamming, planning hulls, high-speed hydrodynamics of seaplanes, surface-piercing propellers and the interaction of high-speed liquid drops with structural elements. Asymmetric water entry may be caused by various natural phenomena such as weather conditions or strong winds. Since the determination of hydrodynamic impact load plays a vital role in designing safe and effcient vessels, an accurate and reliable prediction method is necessary to investigate asymmetric water entry problems. In this paper, water entry of a two-dimensional wedge and ship section at constant velocity in asymmetric condition will be analysed numerically and the effects of asymmetric impact on the velocity and pressure distributi...

Research paper thumbnail of Study on the Development of Water Transport Network for Passengers in the Gulshan-Banani-HatirJheel Lake of the Capital City of Bangladesh

Journal of Shipping and Ocean Engineering, 2015

Dhaka, the capital city of Bangladesh is one of the most overpopulated city in the world and traf... more Dhaka, the capital city of Bangladesh is one of the most overpopulated city in the world and traffic jam is the most severe and regular affliction in the daily life. Also, the existing vehicles are not sufficient in compared to the population of the city. People have to spend many hours simply sitting in the traffic jam. This lessens the productivity of people and brings sufferings to them. Gulshan-Banani-HatirJheel area is the busiest regions within the city and face severe traffic jam during working hours. These lakes are totally unused. Therefore, there is a possibility to build a waterways network for passengers transport through these lakes. This will reduce the affliction of people via reducing traffic jam. The proposed transportation networks will also preserve the natural environment of the lakes and bring a source of entertainment in the city life. Many developed cities in the world like London, New York, Paris, Venice, Shanghai etc. already have implemented waterways network inside the city and successfully made the best use of cistern side.

Research paper thumbnail of Comparative Study of RaNS and PF based Solver for Predicting Added Resistance of a Very Large Crude Carrier

Procedia Engineering, 2017

Computational ship hydrodynamics has gained high popularity in shipbuilding industry in recent ye... more Computational ship hydrodynamics has gained high popularity in shipbuilding industry in recent years because of its high efficiency and improved accuracy. Reliable performance prediction at design stage is essential for large structures, like ships, to ensure design conformance and buyer 's acceptance. Thus, shipbuilders are emphasizing and relying more and more on computational methods. This paper aims at providing a comparative study of added resistance and related motion prediction using a Reynolds averaged Navier-Stokes (RaNS) and potential flow (PF) based solver, for a very large crude career, KVLCC2. The used RaNS solver, SHIP Motion, solves overset structured mesh using finite volume method. The PF solver is a commercial solver named HydroSTAR that uses 3D panel method for simulation and prediction. The paper compares both the results and shows that the RaNS solver is better in predicting added resistance, however, in case of motion predicting, both show similar level of accuracy.