Advanced Aerodynamics and Hydrodynamics for Powerboats

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TBDP©/VBDP© Hump Transition Analysis
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  BREAKTHROUGH!

Figure 1- TBDP©/VBDP© identifies the 'Hump Transition' Velocity.
  The 'Hump Zone' exists on all performance hulls, and can indicate a point of instability of interest to performance optimization.

The 'hump zone' marks the velocity region of inherent 'instability' due to the significant transfer of Lift mechanism. This 'hump' or 'transition zone' occurs on all performance boats, and is different with each hull and setup. When driving the boat you can often experience this change in Lift as the additional lift mechanism becomes more useful.

For tunnel hulls, the 'hump zone' is usually the transition velocity at which aerodynamic (deck/tunnel) Lift forces start generating more significant contributing Lift to the hull performance, and Lift from sponson surfaces become more efficient due to reduced wetted surfaces.

For Vee-Pad hulls, the 'hump zone' is usually the transition velocity when efficient hydrodynamic forces of the Vee-Pad start generating more significant contributing Lift, and Lift from vee surfaces become more efficient due to reduced wetted surfaces.

'Hump Zone' characteristics are helpful when considering dynamic stability of hull, performance of vee-pad feature, centerpod feature, and when designing hull Steps, Lift Strakes.

The point (velocity) of instability is somewhat difficult to predict - but we have a mathematical method to accurately predict the onset of instability and the point of the 'Hump Zone Transition".

TBDP©/VBDP© software analyzes d(CFDynamic, V) and d(SWet, V) to determine the velocity range of onset of "Hump Transition zone".

TBDP©/VBDP© does analysis to determine velocities and characteristics of the'hump zone' and provides narrative description specific to your hull design and setup.

[Note: more information/research paper on Dynamic Stability here]

     

Research results now included in performance analysis by TBDP©/VBDP©

[more about AR's research     more about AR's publications    and    technical articles/papers]
 
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©Copyright by AeroMarine Research and Jim Russell, 1999, all rights reserved.
Material from this website may be not copied or used or redistributed, in whole or in part, without specific written consent of Jim Russell or AeroMarine Research®.