A numerical study of planing hydrodynamics using strips of variable pressure
A numerical study of planing hydrodynamics using strips of variable pressure
A pressure strip method is presented for the prediction of hydrodynamic forces acting on a planing craft moving on the surface of calm water. Within the frame of linearized potential flow theory, the presence of a planing craft is represented by an assemblage of strips of transversely variable pressure placed on the mean free surface. The unknown pressure distribution on each strip is represented by a sine series with unknown coefficients which are determined by solving an integral equation relating the pressure distribution to the water surface elevation underneath the craft. Hydrodynamic parameters can easily be calculated once the pressure distribution on each strip is determined. In the present approach, the transom profile of a planing craft and the depth of its immersion are determined as a part of solution, while the wetted area of the planing hull projected on to the undisturbed free surface is prescribed in advance as input data. Numerical computations are carried out for a number of 3-D planing surfaces of various profiles, including flat plates, prismatic hulls and other hulls with variable deadrise angles. 2-D planing is also studied as a special case of large aspect ratio 3-D planing problem. The planing in heel and drift conditions is studied for flat and prismatic hulls, and the effects of heel and drift on the hydrodynamic force and moments acting on the craft are discussed. The present results are compared with other authors' numerical results, which showed significant improvement in pressure convergence for flat planing hulls without heel or drift, and the wider range of running conditions the present theory can be applied to. Comparisons are also made with experimental data when available and generally good agreement is achieved.
University of Southampton
Cheng, Xiaoming
28ea3438-e9a3-463b-949e-5f4f9823022b
1992
Cheng, Xiaoming
28ea3438-e9a3-463b-949e-5f4f9823022b
Cheng, Xiaoming
(1992)
A numerical study of planing hydrodynamics using strips of variable pressure.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
A pressure strip method is presented for the prediction of hydrodynamic forces acting on a planing craft moving on the surface of calm water. Within the frame of linearized potential flow theory, the presence of a planing craft is represented by an assemblage of strips of transversely variable pressure placed on the mean free surface. The unknown pressure distribution on each strip is represented by a sine series with unknown coefficients which are determined by solving an integral equation relating the pressure distribution to the water surface elevation underneath the craft. Hydrodynamic parameters can easily be calculated once the pressure distribution on each strip is determined. In the present approach, the transom profile of a planing craft and the depth of its immersion are determined as a part of solution, while the wetted area of the planing hull projected on to the undisturbed free surface is prescribed in advance as input data. Numerical computations are carried out for a number of 3-D planing surfaces of various profiles, including flat plates, prismatic hulls and other hulls with variable deadrise angles. 2-D planing is also studied as a special case of large aspect ratio 3-D planing problem. The planing in heel and drift conditions is studied for flat and prismatic hulls, and the effects of heel and drift on the hydrodynamic force and moments acting on the craft are discussed. The present results are compared with other authors' numerical results, which showed significant improvement in pressure convergence for flat planing hulls without heel or drift, and the wider range of running conditions the present theory can be applied to. Comparisons are also made with experimental data when available and generally good agreement is achieved.
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Published date: 1992
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Local EPrints ID: 461850
URI: http://eprints.soton.ac.uk/id/eprint/461850
PURE UUID: bc073e12-54e8-4c4f-bebb-2dcb994136bc
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Date deposited: 04 Jul 2022 18:57
Last modified: 04 Jul 2022 18:57
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Author:
Xiaoming Cheng
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