A Relationship Between Wave Drag and Induced Drag

Application of Ship-Wave Theory to the Hydrofoil of Finite Span

Journal of Ship Research ◽

10.5957/jsr.1957.1.2.27 ◽

1957 ◽

Vol 1 (02) ◽

pp. 27-55

Author(s):

John P. Breslin

Keyword(s):

Wave Theory ◽

Wave Pattern ◽

Wave Drag ◽

Test Results ◽

Dimensional Theory ◽

Ship Hydrodynamics ◽

Finite Span ◽

Induced Drag ◽

Load Distributions ◽

The Waves

It is demonstrated in this paper2 that the deepwater wave drag of a hydrofoil of finite span can be found directly from the theory developed largely for ship hydrodynamics by Havelock and others. The wave drag is then studied at high Froude numbers and from the observed behavior the induced drag of the hydrofoil can be deduced from existing aerodynamic formulas. Evaluation of the resulting formulas is effected for two arbitrary load distributions and a comparison with some model test results is made. A practical approximation which gives the influence of gravity over a range of high Froude numbers is found and from this one can deduce a Froude number beyond which the effects of gravity may be ignored. It is also shown that an expression for the waves at some distance aft of the hydrofoil can be deduced from the general formulas developed for ship hydrodynamics. A discussion of the wave pattern is given with particular emphasis on the centerline profile at high Froude numbers and a contrast is pointed out in regard to the results of the two-dimensional theory for the hydrofoil waves and wave resistance.

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SPLASH Nonlinear and Unsteady Free-Surface Analysis Code for Grand Prix Yacht Design

10.5957/csys-1997-014 ◽

1997 ◽

Author(s):

Bruce S. Rosen ◽

Joseph P. Laiosa

Keyword(s):

Free Surface ◽

Free Surface Flow ◽

Inviscid Flow ◽

Wave Drag ◽

Surface Flow ◽

Viscous Drag ◽

Accurate Estimation ◽

Following Seas ◽

Induced Drag ◽

Lifting Surfaces

The SPLASH free-surface potential flow panel code computer program is presented. The 3D flow theory and its numerical implementation are discussed. Some more conventional applications are reviewed, for steady flow past solid bodies, and for classical linearized free-surface flow. New free-surface capabilities are also described, notably, steady nonlinear solutions, and novel unsteady partiallynonlinear solutions in the frequency domain. The inviscid flow method treats both free-surface waves and lifting surfaces. The calculations yield predictions for complex interactions at heel and yaw such as wave drag due to lift, the effect of the freesurface on lift and lift-induced drag, and unsteady motions and forces in oblique or following seas. These are in addition to the usual predictions for the simpler effects considered separately, for example double-body lift and induced drag, and upright steady wave resistance or added resistance in head seas. For prediction of total resistance, the use of computed variable wetted areas and wetted lengths in a standard semi-empirical, handbook-type "viscous stripping" algorithm provides a more accurate estimation of viscous drag than is possible otherwise. Results from a variety of IACC and IMS yacht design studies, including comparisons with experimental data, support the conclusion that the freesurface panel code can be used for reliable and accurate prediction of sailboat performance.

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Comparison of oblique shock wave angle in analytical and numerical solution

Aerospace Research in Bulgaria ◽

10.3897/arb.v31.e12 ◽

2019 ◽

Vol 31 ◽

pp. 137-142 ◽

Cited By ~ 1

Author(s):

Assen Marinov

Keyword(s):

Shock Wave ◽

Shock Waves ◽

Wave Drag ◽

Oblique Shock Wave ◽

Friction Drag ◽

Total Drag ◽

Induced Drag ◽

Drag And Lift ◽

Wave Angle

The drag of the subsonic aircraft is largely formed by the skin friction drag and lift-induced drag. At transonic flight occurs shock wave. Determination of shock wave angle is important part of design of every aircraft, which working in supersonic airflow regimes. Formation of shock waves cause formation the wave drag. The wave drag could account about 35% from total drag of aircraft. Shock wave angle is directly linked with the intensity of itself. This work compares shock wave angle calculations using analytical and numerical solving methods.

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Accurate decomposition method and identification technology of drag

International Journal of Modern Physics B ◽

10.1142/s0217979220401141 ◽

2020 ◽

Vol 34 (14n16) ◽

pp. 2040114

Author(s):

Jia-Lei Yu ◽

Jing Jin ◽

Chun Shao ◽

Miao Zhang ◽

Tie-Jun Liu

Keyword(s):

Shock Wave ◽

Integral Method ◽

Physical Mechanism ◽

Wave Drag ◽

Irreversible Processes ◽

Viscous Drag ◽

Numerical Dissipation ◽

Far Field ◽

Induced Drag ◽

Field Integral

Aiming at accurate decomposition and identification of drag, the drag prediction technology based on the mid/far-field integral method is developed. The method decomposes the far-field drag into entropy drag and induced drag according to its physical mechanism, and introduces an appropriate entropy correction to eliminate the numerical dissipation by analyzing the influence of the trailing integral section position on the entropy drag calculation. Based on the analysis of thermodynamic reversible processes and irreversible processes, the drag is refined into viscous drag, shock wave drag, induced drag and pseudo-drag. The mid-field integral method is used to calculate the separate contribution of viscous drag, shock wave drag and induced drag by calculating the limited integral domain. Numerical results show that the developed method is feasible in accurately reflecting the physical mechanism and predicting the drag ratio. Thus, it provides a reliable tool for drag reduction of large passenger aircraft.

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The Analysis of Wave Resistance in the Design of the Twelve Meter Yacht Stars & Stripes

10.5957/csys-1987-008 ◽

1987 ◽

Author(s):

Carl A. Scragg ◽

Britton Chance ◽

John C. Talcott ◽

Donald C. Wyatt

Keyword(s):

Wave Drag ◽

Wave Resistance ◽

Great Emphasis ◽

Optimization Techniques ◽

Hydrodynamic Resistance ◽

Design Team ◽

Numerical Techniques ◽

Induced Drag ◽

Hull Optimization ◽

Wave Profiles

During the design of the Twelve Meter yacht STARS AND STRIPES, the design team placed great emphasis upon the minimization of all forms of hydrodynamic resistance: skin friction, lift-induced drag, form drag, and wave resistance. In this paper, the authors discuss methods used to measure, predict, and minimize the wave resistance of Twelve Meter yachts. After a brief review of wave resistance theory, the authors discuss a method by which the wave resistance was determined directly from measured wave-profiles. Numerical techniques used to theoretically predict the curves of wave resistance from the yacht designers' descriptions of hull geometry are examined and the predictions are compared to the experimentally determined wave resistance. Finally, the authors discuss hull optimization techniques, based upon the minimization of the theoretical wave resistance, which enable the yacht designers to develop hull shapes of minimum wave drag.

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Analysis of Wave Resistance in the Design of the 12-Meter Yacht Stars & Stripes

Marine Technology and SNAME News ◽

10.5957/mt1.1987.24.4.286 ◽

1987 ◽

Vol 24 (04) ◽

pp. 286-295

Author(s):

Carl A. Scragg ◽

Britton Chance ◽

John C. Talcott ◽

Donald C. Wyatt

Keyword(s):

Wave Drag ◽

Wave Resistance ◽

Great Emphasis ◽

Optimization Techniques ◽

Hydrodynamic Resistance ◽

Design Team ◽

Numerical Techniques ◽

Induced Drag ◽

Hull Optimization ◽

Wave Profiles

During the design of the 12-Meter yacht Stars & Stripes, the design team placed great emphasis upon the minimization of all forms of hydrodynamic resistance: skin friction, lift-induced drag, form drag, and wave resistance. In this paper, the authors discuss methods used to measure, predict, and minimize the wave resistance of 12-Meter yachts. After a brief review of wave resistance theory, the authors discuss a method by which the wave resistance was determined directly from measured wave profiles. Numerical techniques used to theoretically predict the curves of wave resistance from the yacht designers' description of hull geometry are examined, and the predictions are compared with the experimentally determined wave resistance. Finally, the authors discuss hull optimization techniques, based upon the minimization of the theoretical wave resistance, which enable the yacht designers to develop hull shapes of minimum wave drag.

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