there are different methods to reduce drag in high speed hulls. one of these methods is a change in the shape of the body by adding longitudinal side tunnels. in this paper it has been attempted to determine the influence of the tunnel height on hydrodynamic characteristics of the hull to achieving an optimum shape for the tunnel. to achieve this purpose, numerical simulation of the problem has...

To reduce the ship wave-making resistance, the lines of the bulbous bow of a hull are optimized by an automatic optimization platform at the ship design stage. Parametric modeling was applied to the hull by using non-uniform rational basis spline (NURBS). The Rankine-source panel method was used to calculate the wave-making resistance. A hybrid optimization strategy was applied to achieve the o...

We introduce order-k α-hulls and αshapes — generalizations of α-hulls and α-shapes. Being also a generalization of k-hull (known in statistics as “k-depth contour”), order-k α-hull provides a link between shape reconstruction and statistical depth. As a generalization of α-hull, order-k α-hull gives a robust shape estimation by ignoring locally up to k outliers in a point set. Order-k α-shape p...

The asymptotic properties of Rapidly exploring Random Tree (RRT) growth in large spaces is studied both in simulation and analysis. The main phenomenon is that the convex hull of the RRT reliably evolves into an equilateral triangle when grown in a symmetric planar region (a disk). To characterize this and related phenomena from flocking and swarming, a family of dynamical systems based on incr...

An application of Fourier descriptors and convex hull for shape analysis is presented. Convex hull is used for dividing a shape into small parts. Amplitude spectrum which is invariant to scaling, translation and choosing a starting point is obtained from the Fourier descriptors (see e.g [1-3]) and used for comparison. All calculations are performed with the author's software and some algorithms...

Of late, researchers appear to be intrigued with the question; Given a set of points, what is the region occupied by them? The answer appears to be neither straight forward nor unique. Convex hull, which gives a convex enclosure of the given set, concave hull, which generates nonconvex polygons and other variants such as α-hull, poly hull, r-shape and s-shape etc. have been proposed. In this pa...

Development of autonomous underwater vehicles (AUVs) which meets the design constraints and provides the best hydrodynamic performance is really an important challenge in the field of hydrodynamics. In this paper a new profile is used for designing the hull of AUVs. The nose and tail profiles of an AUV using presented profile is designed such that it can properly consider the length constraints...

In designing for ship production, the production method should be considered and it’s possible to reduce the manufacturing cost in designing procedure. A review of background of ship design that had minimized production costs, shows the principles and problems of these methods. Modern designing methods for manufacturing, considers hydrodynamic efficiency and less manufacturing cost. Quant...