Tomasz; van der Ploeg Gornics, Auke; Scholcz
Trim wedge optimization with viscous free surface computations Conference
Proceedings of PRADS2016, Copenhagen, Denmark, 2016.
@conference{Gornics2016,
title = {Trim wedge optimization with viscous free surface computations},
author = {Gornics, Tomasz; van der Ploeg, Auke; Scholcz, Thomas},
url = {http://www.marin.nl/web/Publications/Papers/Trim-wedge-optimization-with-viscous-free-surface-computations.htm},
year = {2016},
date = {2016-09-04},
booktitle = {Proceedings of PRADS2016, Copenhagen, Denmark},
abstract = {A procedure for automatic optimization of a ship hull and
trim wedge is described, that is based on an evaluation
of a series of hull form/trim wedge combinations. These
evaluations are done with a RANS method that can accurately
and efficiently compute the viscous flow for several
transom flow regimes, ranging from completely dry
to (partly) wetted. The object function is an approximation
of the required power to maintain a given speed. Results
obtained from several trim wedge optimizations are
shown, computed and measured trends are compared and
computed scale effects in those trends are discussed. For
two examples, a considerable improvement of the object
function can be obtained. At full scale, the improvement
of the object function is stronger than at model scale.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
trim wedge is described, that is based on an evaluation
of a series of hull form/trim wedge combinations. These
evaluations are done with a RANS method that can accurately
and efficiently compute the viscous flow for several
transom flow regimes, ranging from completely dry
to (partly) wetted. The object function is an approximation
of the required power to maintain a given speed. Results
obtained from several trim wedge optimizations are
shown, computed and measured trends are compared and
computed scale effects in those trends are discussed. For
two examples, a considerable improvement of the object
function can be obtained. At full scale, the improvement
of the object function is stronger than at model scale.
M. Kerkvliet, Carette; Straten, O. van
Analysis of free surface anti-roll tank using URANS. Verification and validation Conference
13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark, 2016.
@conference{Kerkvliet2016,
title = {Analysis of free surface anti-roll tank using URANS. Verification and validation},
author = {Kerkvliet, M., Carette, N. and Straten, O. van},
url = {http://www.marin.nl/web/Publications/Papers/Analysis-of-free-surface-antiroll-tank-using-URANS.-Verification-and-validation-1.htm},
year = {2016},
date = {2016-09-04},
booktitle = {13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark},
pages = {ID055},
abstract = {To prevent excessive roll motion of ships operating in seas, damping systems are often required. Exterior systems can be used like, bilge keels or active stabilizer fins, or interior systems like anti-roll tanks (ARTs). There are mainly two sorts of ARTs, i.e. free surface tanks and Utype tanks. Both types have been studied extensively in the past, e.g. by Watts (1883), Frahm (1911) and Verhagen and Wijngaarden (1965), but also more recently, e.g. by Lee and Vassalos (1996), Kerkvliet et al. (2014) and Carette (2015). The content of this paper is restricted to the free surface type ART, which is nowadays often used to increase the roll damping of ships passively. The main advantages of such an ART are the large damping moment at small roll amplitudes and the ease to adapt the response by changing the water level. The response of the tank is highly frequency and amplitude dependent with a strong non-linear character (Carette et al., 2016). Also the shape of the interior geometry, e.g. additional struts, plates or other flow obstructions, will have an effect on the response, which makes it difficult to predict the response by analytical models. Therefore, systematic oscillation tests are often performed by model-scale experiments or by use of Computational Fluid Dynamics (CFD). This paper shows the response of a two-dimensional (2D) and three-dimensional (3D) model-scale free surface ART using the CFD code ReFRESCO (www.refresco.org). The objective of this paper is to show which issues are important when CFD is used as a research and design tool. A verification and validation study is performed to determine numerical settings to obtain a good trade-off between accuracy and computational costs. The CFD results are validated against model-scale experimental results, based on the work of Carette (2015). The results show that CFD can be used as a simulation driven design tool to accurately predict the response of an ART.},
keywords = {},
pubstate = {published},
tppubtype = {conference}
}
2016
Tomasz; van der Ploeg Gornics, Auke; Scholcz
Trim wedge optimization with viscous free surface computations Conference
Proceedings of PRADS2016, Copenhagen, Denmark, 2016.
Abstract | Links | BibTeX | Tags: CFD, free surface, optimization, scale effects, ship hydrodynamics, trim wedge
@conference{Gornics2016,
title = {Trim wedge optimization with viscous free surface computations},
author = {Gornics, Tomasz; van der Ploeg, Auke; Scholcz, Thomas},
url = {http://www.marin.nl/web/Publications/Papers/Trim-wedge-optimization-with-viscous-free-surface-computations.htm},
year = {2016},
date = {2016-09-04},
booktitle = {Proceedings of PRADS2016, Copenhagen, Denmark},
abstract = {A procedure for automatic optimization of a ship hull and
trim wedge is described, that is based on an evaluation
of a series of hull form/trim wedge combinations. These
evaluations are done with a RANS method that can accurately
and efficiently compute the viscous flow for several
transom flow regimes, ranging from completely dry
to (partly) wetted. The object function is an approximation
of the required power to maintain a given speed. Results
obtained from several trim wedge optimizations are
shown, computed and measured trends are compared and
computed scale effects in those trends are discussed. For
two examples, a considerable improvement of the object
function can be obtained. At full scale, the improvement
of the object function is stronger than at model scale.},
keywords = {CFD, free surface, optimization, scale effects, ship hydrodynamics, trim wedge},
pubstate = {published},
tppubtype = {conference}
}
trim wedge is described, that is based on an evaluation
of a series of hull form/trim wedge combinations. These
evaluations are done with a RANS method that can accurately
and efficiently compute the viscous flow for several
transom flow regimes, ranging from completely dry
to (partly) wetted. The object function is an approximation
of the required power to maintain a given speed. Results
obtained from several trim wedge optimizations are
shown, computed and measured trends are compared and
computed scale effects in those trends are discussed. For
two examples, a considerable improvement of the object
function can be obtained. At full scale, the improvement
of the object function is stronger than at model scale.
M. Kerkvliet, Carette; Straten, O. van
Analysis of free surface anti-roll tank using URANS. Verification and validation Conference
13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark, 2016.
Abstract | Links | BibTeX | Tags: anti-roll tank, ART, CFD, free surface, ReFRESCO, URANS, verification and validation
@conference{Kerkvliet2016,
title = {Analysis of free surface anti-roll tank using URANS. Verification and validation},
author = {Kerkvliet, M., Carette, N. and Straten, O. van},
url = {http://www.marin.nl/web/Publications/Papers/Analysis-of-free-surface-antiroll-tank-using-URANS.-Verification-and-validation-1.htm},
year = {2016},
date = {2016-09-04},
booktitle = {13th International Symposium on Practical Design of Ships (PRADS), Copenhagen, Denmark},
pages = {ID055},
abstract = {To prevent excessive roll motion of ships operating in seas, damping systems are often required. Exterior systems can be used like, bilge keels or active stabilizer fins, or interior systems like anti-roll tanks (ARTs). There are mainly two sorts of ARTs, i.e. free surface tanks and Utype tanks. Both types have been studied extensively in the past, e.g. by Watts (1883), Frahm (1911) and Verhagen and Wijngaarden (1965), but also more recently, e.g. by Lee and Vassalos (1996), Kerkvliet et al. (2014) and Carette (2015). The content of this paper is restricted to the free surface type ART, which is nowadays often used to increase the roll damping of ships passively. The main advantages of such an ART are the large damping moment at small roll amplitudes and the ease to adapt the response by changing the water level. The response of the tank is highly frequency and amplitude dependent with a strong non-linear character (Carette et al., 2016). Also the shape of the interior geometry, e.g. additional struts, plates or other flow obstructions, will have an effect on the response, which makes it difficult to predict the response by analytical models. Therefore, systematic oscillation tests are often performed by model-scale experiments or by use of Computational Fluid Dynamics (CFD). This paper shows the response of a two-dimensional (2D) and three-dimensional (3D) model-scale free surface ART using the CFD code ReFRESCO (www.refresco.org). The objective of this paper is to show which issues are important when CFD is used as a research and design tool. A verification and validation study is performed to determine numerical settings to obtain a good trade-off between accuracy and computational costs. The CFD results are validated against model-scale experimental results, based on the work of Carette (2015). The results show that CFD can be used as a simulation driven design tool to accurately predict the response of an ART.},
keywords = {anti-roll tank, ART, CFD, free surface, ReFRESCO, URANS, verification and validation},
pubstate = {published},
tppubtype = {conference}
}