Geometric linearization of theories for incompressible elastic materials and applications

We derive geometrically linearized theories for incompressible materials from nonlinear elasticity theory in the small displacement regime. Our nonlinear stored energy densities may vary on the same (small) length scale as the typical displacements. This allows for applications to multiwell energies as, e.g. encountered in martensitic phases of shape memory alloys and models for nematic elastomers. Under natural assumptions on the asymptotic behavior of such densities we prove Gamma-convergence of the properly rescaled nonlinear energy functionals to the relaxation of an effective model. The resulting limiting theory is geometrically linearized in the sense that it acts on infinitesimal displacements rather than finite deformations, but will in general still have a limiting stored energy density that depends in a nonlinear way on the infinitesimal strains. Our results, in particular, establish a rigorous link of existing finite and infinitesimal theories for incompressible nematic elastomers.

Numerical Study of Hydrodynamics of Heavily Loaded Hard-Chine Hulls in Calm Water

Hard-chine boats are usually intended for high-speed regimes where they operate in the planing mode. These boats are often designed to be relatively light, but there are special applications that may occasionally require fast boats to be heavily loaded. In this study, steady-state hydrodynamic performance of nominal-weight and overloaded hard-chine hulls in calm water is investigated with computational fluid dynamics solver program STAR-CCM+. The resistance and attitude values of a constant-deadrise reference hull and its modifications with more pronounced bows of concave and convex shapes are obtained from numerical simulations. On average, 40% heavier hulls showed about 30% larger drag over the speed range from the displacement to planing modes. Among the studied configurations, the hull with a concave bow is found to have 5–12% lower resistance than the other hulls in the semi-displacement regime and heavy loadings and 2–10% lower drag in the displacement regime and nominal loading, while this hull is also capable of achieving fast planing speeds at the nominal weight with typical available thrust. The near-hull wave patterns and hull pressure distributions for selected conditions are presented and discussed as well.

Predicting development parameters for gas-condensate deposits with oil banks in the exploitation of horizontal wells

The paper presents comparative analysis of technological parameters of depletion and water-oil displacement modes during the exploitation of oil banks in gas-condensate deposit with horizontal well in gas-free production rates based on the three-phase multi-component filtration model. In water-oil displacement regime the oil recovery factors were higher compared to the depletion mode. The development profitability was justified. The increase of oil recovery factor in water-oil displacement regime is achieved due to the weak rate of flooding in well production and unrecoverable capacity of the fluid injected into the reservoir. The practicability of oil banks exploitation in gas-condensate deposit in gas-free rates at the first stage of development in depletion and in water-oil displacement modes at further stage correspondingly is justified.

Transonic Hull: Theory, Validation, Breakthroughs and Applications to Ships

Froude laws are inductive therefore not universally applicable. The relation between Froude and Kelvin, and Froude and Wigley are made explicit. Transonic Hull (TH) has hydrodynamic characteristics not predictable by Froude’s laws. In Transonic Hydrofield (THF) Theory TH’s 3-D triangular shape induces a submerged current - subduction effect - that replaces and substantially precludes bow wave, reducing or eliminating wave making drag growth. TH’s ability to transverse waves without diminishing their energy eliminates slam. TH’s unprecedented breakthroughs with large magnitude are: substantially no bow or stern wave; full displacement regime and near zero pitch independent of speed; linear drag-speed function with greatly reduced wave making (residual) drag; accelerations in a sea that decrease with increasing speed; no slam at any speed and sea conditions. CFD studies of TH-900 vs. Fastship and TH-4022 vs. Axe Bow 4103 shows reduction of drag from 20% to 37% with gains of weight/drag from 33% to 59%. Gains originate from much smaller residual drag. Pre-feasibility studies demonstrate that TH’s triangular waterplanes houses same contents and payloads as conventional vessels provided TH has larger length and beam. TH-1200 Strategic Lift with full payload and range has exceptional high L/D at high speed in Von-Karman-Gabrielli chart.

Detailed single crystal studies on silicates using neutron diffraction

Up to now minerals of the silicate family are an interesting and versatile topic of research. Different members of the epidote, lithium tourmaline and beryl groups with very different structural features were studied on the single crystal diffractometer HEIDI at the hot source of the Heinz Maier-Leibnitz Zentrum in Garching (MLZ) in the recent past. The combination of neutron and X-ray diffraction in combination with other methods revealed for each of the studied minerals valuable information about their structural details. Epidote, an important mineral for metamorphic or magmatic petrology was studied with neutrons at room temperature and at 1070 K. The results confirm the high structural stability with no dehydration and only slight thermal expansion [1]. A combined study with x-ray and neutron diffraction on the complex boro-cyclo-silicate elbaite give insight to the displacement regime and H and O order and disorder respectively [2]. Combined single crystal diffraction with x-rays at room temperature and with neutrons at 2.3 K on pezzottaite, an obverse/reverse twin of the beryl family reveals a complex displacement regime with possible partial H2O replacement [3].