The simplest such shape is probably a V-shape, with the median plane extending across the arms from the centre line of one to the centre line of the other, so that the two free tips/edges are one side and the corner angle is the other. This invention relates to a new and unique technique for an oscillating foil to produce regulated thrust under a hydrodynamically self-adjusted pitching angle that is controlled by damping torque applied about the foil’s pitch or pivot axis. This invention provides a novel technique applicable to oscillating foils or wings to produce both high efficiency and thrust. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a propulsion system based on the principles of thuniform movement, namely the movement of a foil member in a sideways or vertical manner to achieve forward movement of a vehicle or living body. The invention provides a simple, single layer, piezoelectric device-by which is meant that the device has one layer only, and that this layer is made of a piezoelectric material.
Dolor Sordo Profundo Y Continuo
For pitch control, this requires power to drive the motion and a regulation mechanism to vary the magnitude and direction. Depending on the range of precision of the pitch control the damping torque may be controlled mechanically. 14. Together these make effective pairs of electrodes, and in each such pair’s case a small electric field applied using that pair will cause the piezoelectric material in the corrugation to expand or contract, depending on the direction of the field relative to the poling direction. In fact, depending on the torsional elasticity of the damping means or special propulsion needs, this axis may be set far in front of or behind the aerodynamic center. Means are provided for mounting the foil members to a body to be driven through a fluid medium, the mounting means being located at the center of gravity of each such foil member and defining a pivot axis for each foil member, with each foil member being attached to its respective mounting means for limited rotational movement with respect to the body on the pitch axis.
Dolor Neuropático Periférico
Thus, the foil member pitches about the mounting shaft at an angle that is balanced between the damping torque and the hydrodynamic loads on the foil member. Means are connected to the mounting means for driving the mounting means in an oscillatory manner such that during such driving the foil members move towards and away from each other at the same rate. Each foil member has an oscillatory movement applied thereto by the drive means with such movements being opposite to each other whereby during an operational cycle it will be seen that the foil members will move towards and away from each other at the same rate. As the foil members move away from each other more fluid is drawn into the space between the foil members to be compressed and expelled as the system operates. In both the V- and U-shaped devices there are three distinct piezoelectric portion, two in the top group and one in the bottom group.
The upper three belong to one group that is generally planar, and the lower four belong to the other group. Dolor de pierna en la cama . Thus, in FIG. 3A the median plane runs horizontally (as viewed) through the V so that its two tip portions 21 form a generally planar group lying on one side of the median plane MP while its lower v section 22 is the group on the other side. While a simple mechanical form of damping means internal to the foil member has been illustrated, it should be understood that other damping means could be provided, including electrical, magnetic and/or electromagnetic. Unfortunately, it has hitherto not been possible to achieve with a single layer device the relatively large amounts of shape-change movement attainable using the bending ability of a bimorph or even a unimorph. Using a flexible foil or flexible bar-foil configuration for this simple heave-only motion can slightly reduce the problem by increasing the thrust with some sacrifice in efficiency.
While the system of the present invention has been described with respect to a marine type of vehicle, such as an unmanned submarine or research vessel, the principles of operation can be applied to other types of vehicles, including both marine and aerial vehicles, without departing from the spirit of the invention. In its broadest form the present invention may therefore be considered to provide a propulsion system which utilizes a pair of elongated spaced apart foil members. There are many possible “shapes” that can be used to provide the required separation of the body into separate, distinct, portion-containing groups (and some of these are discussed hereinafter with reference to the accompanying Drawings), and perhaps that shape easiest to understand-and therefore best for facilitating comprehension of the concept behind the invention-is that of a simple sheet of corrugated iron (as sometimes employed in the construction of prefabricated buildings).
Dolor De Hombro
A cross-section of the body across its length would reveal the shape of the corrugations (in conventional corrugated iron these are either sinusoidal or they are semicircular; each is satisfactory). These corrugations are straight, and the strip 81 is otherwise flat; in FIG. With reference first of all to FIG. 1 a vehicle 10 is shown therein as having a plurality of propulsion systems 12, 14 in accordance with the present invention mounted thereto.
- Caer mal sobre el pie al saltar o girar
- La frecuencia con la que debes masajear la espalda es de 2 a 5 minutos
- Ciclismo (con precaución)
- Plan antiálgico
- Usar ropa interior de apoyo durante los días siguientes para darle un sostén al testículo
- F05B2250/28-Geometry three-dimensional patterned
- Relajante del músculo liso (carminativo)
2 and 3 it will be seen that the propulsion system of the present invention, whether a system 12 or a system 14, includes a pair of elongated spaced apart foil members 16, 16. Each foil member 16 preferably has a symmetrical aerofoil shape including a bulbous nose portion 18 which tapers rearwardly to a tail portion 20. The foil member 16 can be rigid or it can also be capable of a limited degree of flexibility. The undulation mode is seen in the propulsion of eels (low frequency and large amplitude for low speed swimmers).
Thuniform movement differs from undulating propulsion systems as used by slower moving fish such as eels. 1 shows in a schematic fashion a perspective view of a vehicle with a plurality of propulsion systems in accordance with this invention secured thereto. The invention improves on the efficiency and thrust capabilities of prior systems.
Controlling the damping torque can regulate the thrust production and efficiency. DETAILED DESCRIPTION FIG. 1A shows in perspective a single-layer corrugated piezoelectric device of the invention; it shows how a straight bender can be made from merely a single layer of piezoelectric material and the appropriate electrodes. FIGS. 5A and B show (in perspective) two “S”-bending devices of the invention-that is to say, devices designed, shaped and operated to bend into an S-shape. An application example for the undulation mode is the Nektor™ thrust unit for unmanned underwater vehicles in which a flexible oscillating foil member rotates counterclockwise and clockwise, alternatively, about its pivoting axis to generate thrust.
Dolor Muscular Brazo
This has the effect of compressing the fluid medium between the foil members as they approach each other during each cycle and expelling the compressed fluid rearwardly at the same time to create the desired thrust. In order to achieve 360° of thrust vectoring a small diameter pinion gear 28 co-operates with a geared rack 30 on the inner surface of the pod section.
5, one (the “upper” one) of the pair of foil members is shown at several positions during an operational cycle with a controlled damping torque applied thereto. The solid line foil member profiles illustrate the traditional oscillating foil positions in pure heave and the dashed lines illustrate the profiles for a damped control of the torque. Que causa dolor de espalda . Some oscillating foil propulsors use a simple heave-only motion to save energy and avoid a complicated pitch control mechanism. Pitch of the oscillating foil member is either controlled by a pitch mechanism, such as a flexible bar that is linked to the foil or there is no pitching at all (pure heave motion with a constant pitch angle).
SUMMARY OF THE INVENTION There are two key technologies associated with the present invention. This means that each auto-pitch propeller blade rotates about its individual pivot axis freely (only with friction torque that is nearly zero). Either corrugated form can be utilised to achieve this type of shape change. A further important shape, alluded to above, is that of a (part) ring or annulus, as though a tape-like body were bent round in its own plane, to bring its two ends towards each other to form an object like a broken washer. Dolor de una pierna derecha . However, the corrugations 72 are angled (at about 45 degrees to the long axis A-A of the strip) rather than straight across; since the bending action of the device is only along the length of the corrugations 72, and not perpendicular to them, the angled corrugations 72 have the effect of twisting the strip about its axis A-A.