project biomimetismo
TRANSCRIPT
Instituto Superior TécnicoMestrado Integrado em Engenharia Biológica
2 de Maio de 2014
Projecto de BiomimetismoMid-Term Presentation
BiomimetismoProf. Gabriel Monteiro e Prof. Miguel
Prazeres
Mafalda Marques N.º 67276
Biomimetismo
Índice
Identificação do Problema
Validação do Problema
Soluções Existentes
Solução Biomimética
Biomimetismo
Validação do Problema
A submarine needs to expend a large amount of energy just to keep
moving. Being completely immersed in water, it has to contend with much
higher drag forces than a vehicle traveling through air or a ship moving
on the surface of the water.
Each submarine cost approximately $3 billion to build To operate: $77 million per year per submarine http://www.psr.org/chapters/washington/energy-and-peace/trident.html
Biomimetismo
Soluções Existentes
HULL SHAPEThe key to efficient hull design is
streamlining. A body moving through water is subjected to two retarding forces: form drag and skin friction. The first of these is larger for a blunt body than a tapered one, while the second is larger for a thin body
than a fat one. Minimizing both is a delicate balancing act. The most energy-
efficient design turns out to be a teardrop-shaped hull, in which the length is about 7.7 times the width. It’s no coincidence
that this is the shape found in many fast-swimming fish and marine mammals
Biomimetismo
Soluções Existentes
ENERGY GENERATIONFish spend much of their time feeding,
so their energy supply is constantly being replenished. A submarine, on
the other hand, requires a self-contained energy source that has to
last weeks or months at a time. Some submarines, like those of the U.S.
Navy, have on-board nuclear reactors that have no difficulty meeting the
vessel’s energy needs. Energy supply is more of a problem for non-nuclear
submarines, which traditionally rely on batteries that have to be recharged
using on-board diesel generators. The latest generation of non-nuclear
submarines uses fuel cell technology to provide a much higher level of
energy efficiency.
Biomimetismo
Soluções Existentes
PROPULSION SYSTEMThe most energy-efficient way to
move a submarine through the water is using a large, single-screw propeller. Not all submarines use one, however, because it can generate a lot of noise -- and remaining stealthy and silent is
essential for many submarine operations. As a compromise, a quieter but less efficient ducted
propulsor is used on many modern submarines. The need for stealth also
means submarines are usually designed to operate at slow speeds -- sometimes little more than walking pace -- so as to minimize the noise
generated by the vessel’s machinery. The slow speed of a submarine also
helps to save energy.