1,754 research outputs found
High Speed Marine Vehicles With Aerodynamic Surfaces: Development of a Dynamic Model for a Novel Configuration.
No full textA research programme on high speed marine vehicles fitted with aerodynamic
surfaces started in Cranfield University in 2005. One of the configurations
analyzed is a high speed prismatic planing hull with one or more aerodynamic
surfaces; it is called a hybrid vehicle (HV). Two mathematical models have been
developed for the dynamic behavior which is a combination of the very different
behaviors of aircraft and ships. The first model estimates the equilibrium
attitude of the HV at a certain speed. A parametric analysis for the influence
of the configuration on the performance of the HV has been conducted (1). With
the second model, the authors propose a set of ordinary differential equations
of motion, derived in the frame of small-disturbance stability theory which has
been used to investigate the longitudinal dynamic stability of the HV (2). Ref.
(1) and (2) present a complete description of the mathematical models, while
this article summarizes the methodology adopted to develop these dynamic models
and gives a brief summary of the results. (1) COLLU, M., PATEL, M. H., TRARIEUX,
F., A Mathematical Model to analyze the Static Stability of Hybrid (Aero-
hydrodynamically supported) vehicles., 8th Symposium on High Speed Marine
Vehicles 2008 (HSMV08), Naples, Italy, 2008. (2) COLLU, M., PATEL, M. H.,
TRARIEUX, F., A Unified Mathematical Model for High Speed Hybrid (Air and Water-
borne) Vehicles., 2nd International Conference on Marine Research and
Transportation, 2007
"Chiral Ligands Containing Heteroatoms. 15. Cyclic b-Amino Alcohols as Chiral Inductors for Enantioselective Reductions of Ketones"
No full text
An Automatic Tuning System to Improve Near-Field Powering in Implanted Electronics
No full textDevelopments in the field of inductive charging have opened the door to the use of devices without a battery or with a wireless rechargeable battery. Although this aspect is significant in the field of wearable devices, it is even more significant in the field of transcutaneous connections for implanted electronics and batteries that can greatly benefit the safety and comfort of the patient. The performance on the ability to transmit and store energy through an inductive channel can, however, be influenced by various environmental and manufacturing factors, with significant variations on the effective values of the LC resonant pair. In this regard, an automatic tuning mechanism based on a SAR algorithm implemented in 180nm CMOS technology is proposed
Preliminary scantling design of Aerodynamically Alleviated Marine Vehicles (AAMV)
No full textFor very high speed marine crafts the aerodynamic forces can become of the same order of magnitude as the hydrodynamic ones, especially for small vessels. Although these forces can lead to instability issues in some cases, they can also offer a new range of possibilities to sustain the weight of the craft. The vessel can be equipped with aerodynamic lifting surfaces in order to alleviate the weight of the vehicle, leading to a lower effective displacement, hence lower resistance and required power.
The estimation of the total weight of the vehicle and of its distribution is of paramount importance, since it strongly affects the whole design process. Due to the lack of commercially established AAMV configurations, and due to the substantial differences between AAMV and other fast vehicles, regressions based on historical data derived from present and past vehicles are not available. The proposed approach is therefore based on the High Speed Craft Code and on first principles of structural engineering, considering both global and local behaviour of structural components. The developed procedure works out an estimate of the weight of the structure using as input data only the main characteristics of the AAMV under design and it represents a starting point in the scantling design of an AAMV in the first steps of the design spiral
On mooring line tension and fatigue prediction for offshore vertical axis wind turbines: A comparison of lumped mass and quasi-static approaches
No full textDespite several potential advantages, relatively few studies and design support tools have been developed for floating vertical axis wind turbines. Due to the substantial aerodynamics differences, the analyses of vertical axis wind turbine on floating structures cannot be easily extended from what have been already done for horizontal axis wind turbines. Therefore, the main aim of the present work is to compare the dynamic response of the floating offshore wind turbine system adopting two different mooring dynamics approaches. Two versions of the in-house aero-hydro-mooring coupled model of dynamics for floating vertical axis wind turbine (FloVAWT) have been used, employing a mooring quasi-static model, which solves the equations using an energetic approach, and a modified version of floating vertical axis wind turbine, which instead couples with the lumped mass mooring line model MoorDyn. The results, in terms of mooring line tension, fatigue and response in frequency have been obtained and analysed, based on a 5 MW Darrieus type rotor supported by the OC4-DeepCwind semisubmersible
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