Monday, 23 February 2015
Thursday, 19 February 2015
Thursday, 5 February 2015
Different Types Of Wave generators
Flap-type Wave Generator with
Single Articulation
PRINCIPLES~
This is a flap oscillating about an axis located at the channel bed or a certain distance above the bed. The edge of .the paddle may descend to the articulation axis or stop at a certain distance from this axis . The motion imparted to the water is zero at the channel bed. Therefore; this wave generator is not adaptable in principle except to waves of infinite depth, that is~ such that the wave length is less than twice the depth. In actuality the device yields good results even at very shallow depth.
CONSTRUCTION :
~The construction is very simple; the flap may be made quite strong and rigid by means of proper shaping.
INERTIA :
The inertia is relatively small.
MAINTENANCE:
The single hinge is in the water, it can be quite simple and, its maintenance slight.
REFLECTION CHARACTERISTICS~
The flap is reflective, as demonstrated by theory and experience, yet its real reflection coefficient is smaller than the theoretical coefficient because of leakages along the walls, breaking, and turbulence.
PRINCIPLES~
This is a flap oscillating about an axis located at the channel bed or a certain distance above the bed. The edge of .the paddle may descend to the articulation axis or stop at a certain distance from this axis . The motion imparted to the water is zero at the channel bed. Therefore; this wave generator is not adaptable in principle except to waves of infinite depth, that is~ such that the wave length is less than twice the depth. In actuality the device yields good results even at very shallow depth.
~The construction is very simple; the flap may be made quite strong and rigid by means of proper shaping.
INERTIA :
The inertia is relatively small.
MAINTENANCE:
The single hinge is in the water, it can be quite simple and, its maintenance slight.
REFLECTION CHARACTERISTICS~
The flap is reflective, as demonstrated by theory and experience, yet its real reflection coefficient is smaller than the theoretical coefficient because of leakages along the walls, breaking, and turbulence.
Maintaining an Adequate Wave Amplitude
It is known that the use of wave filters causes a decrease in the amplitude of the genera ted wave. This disadvantage may constitute a source of trouble in certain tests" usually of a theoretical nature, in which it is desired to obtain waves of large steepness. In this case» it is necessary to intensify the wave after' it has traversed the filters ~
Two methods. which can be applied separately or' simultaneously" have been investigated at the Dauphin Hydraulic Laboratory (Neyrpic) for several year so,
The first method consists of installing downstream of the filters a convergent channel where the wave is intensified;
The second method consists of raising the channel bed downstream of the filters', this has little effect on the wave amplitude (the amplitude even decreases in certain cases) but. shortening the wave length» finally increases the wave steepness.
Thanks to such arrangements" . It should be noted, nevertheless, that the first ,method is used more generally than the second method, which makes it possible to obtain appreciable intensification of the waves only when the ratio of depth to wave length is sufficiently small"
Phase 1 : Understanding Wave Motion and its Characteristics
Starting With the Quest .
Let us go through some basics of
Wave motion characteristics and key ingredients to deal with.
A~. Inertia
It is essential to assign to the wave generator a small inertia sufficient to assume rigidity and solidity. To enable the member~ to resist stresses, it is necessary to increase the dimensions, hence the mass and,consequently, the inertia of these members •.This increase . involves two detrimental effects: the . required motor power to.overcome the passive resistances and the inertia forces is greatly increased, and the motion .,' is quite irregular because. of these forces.
B;, Maintenance
Maintenance of the apparatus similarly poses problems to the designers •. It is necessary to avoid as much as possible using in the water any delicate members, articulations, bearings, rollers, or gears. In addition to the danger of corrosion, it is essential to remember that the water often contains sand either in the model structures as such or because the. model comprises a mobile bed.
C. Reflection
In reality, the waves reflect .'from a given structure tend to depart seaward where they become dissipated; in a model, however, they recoil toward the Wave generator. Both theory (presented subsequently in Biesels 13 article) and practice show that most wave generators are quite reflective.
There seem to exist two remedies for this disadvantage.
a) The first is the use of a filter
b)The second is the use of' special method Or wave generators with little reflection
Let us go through some basics of
Wave motion characteristics and key ingredients to deal with.
A~. Inertia
It is essential to assign to the wave generator a small inertia sufficient to assume rigidity and solidity. To enable the member~ to resist stresses, it is necessary to increase the dimensions, hence the mass and,consequently, the inertia of these members •.This increase . involves two detrimental effects: the . required motor power to.overcome the passive resistances and the inertia forces is greatly increased, and the motion .,' is quite irregular because. of these forces.
B;, Maintenance
Maintenance of the apparatus similarly poses problems to the designers •. It is necessary to avoid as much as possible using in the water any delicate members, articulations, bearings, rollers, or gears. In addition to the danger of corrosion, it is essential to remember that the water often contains sand either in the model structures as such or because the. model comprises a mobile bed.
C. Reflection
In reality, the waves reflect .'from a given structure tend to depart seaward where they become dissipated; in a model, however, they recoil toward the Wave generator. Both theory (presented subsequently in Biesels 13 article) and practice show that most wave generators are quite reflective.
There seem to exist two remedies for this disadvantage.
a) The first is the use of a filter
b)The second is the use of' special method Or wave generators with little reflection
Wednesday, 4 February 2015
Project Animation Wave Energy Converter!
This video illustrates an interesting wave energy conversion technology called the Ocillo drive
Source: wavewaterworks.com
http://paksc.org/video/alternative-energy/299-wave-energy-converter-project-animation
This video illustrates an interesting wave energy conversion technology called the Ocillo drive
Source: wavewaterworks.com
http://paksc.org/video/alternative-energy/299-wave-energy-converter-project-animation
Renewable Energy !!
The Department of Energy (DOE) has launched a multiple-year effort to validate the extent to which control strategies can increase the power produced by resonant wave-energy converter (WEC) devices. Many theoretical studies have shown a promise that additional energy can be captured by controlling the power-conversion chains of resonant WEC devices.
http://energy.sandia.gov/energy/renewable-energy/water-power/in-the-news-water-power-clean-energy-research/
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