Patent Application
20120145066
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The field of this invention relates generally to drag, stealth, vortices, and propulsion in subsurface craft. More specifically it relates to managing specific Apparent Flows over selected Surface Treatment to exploit those forces available and generate distributed propulsion in underwater craft and devices.
The fore-aft motion of Fixed Hulls is generally affect most by skin drag which produces vortices in the boundary layer. The energy stored in the angular momentum of the fluid or vortices coalesces in the boundary layer and shear layer and forms large vortices or break away vortices known as von Karman vortices. As these eddies are shed or separate from the craft they do so at great expense or drag to the efficient fore-aft motion of the craft.
With Fixed Hulls, all net drag forces traditionally are overcome by the propeller or centralized propulsion system which as the craft increases in size and speed increases the problem of hydrodynamic noise and cavitation around the propulsion system. The application of power to the rear of a craft creates an inverted pendulum, with stability and guidance problems. The application of power or guidance to the forward position of a craft cause turbulent flows that increase drag and noise aft down the length of the craft. The stern drive requires the vehicle to be pushed through the water, which generates geometrically disproportionate wave drag resistance with any increase in speed. This frontal wave generation limits stability, efficiency and speed. Most importantly the more concentrated approach to thrust gives an uneven pulsating noisy result.
A moving submerged vessel or underwater craft that is subject to hydrodynamic noise is easily detected, located and identified as these noises have a unique quality for each craft. Stealth is generally a high priority in underwater craft such as submarines with velocity being the factor that has been reduced to maintain stealth. U.S. Pat. No. 6,659,030 and U.S. Pat. No. 3,779,199 are two examples that sucked and ejected large volumes of fluids to vary the turbulent field and improve propulsion. They require large pumps or propellers that would cause large Reynolds numbers and noisy cavitation in an underwater craft.
With traditional fore-aft motion on Fixed Hulls, random vortices using scales or texturing can be developed with slight benefit thus giving surface texturing or scales a small statistical advantage over a smooth skinned Fixed Hull as seen in U.S. Pat. No. 5,171,623. Vortex Generators (VG) on Fixed Hulls or wings have only been beneficial at certain times and not at others and thus within the art there are controllable or Variable VG that are utilized during take off and landings and not during cruise conditions. A Variable VG is illustrated in U.S. Pat. No. 6,427,948.
U.S. Pat. No. 4,516,747 is a method for controlling the flow in the boundary layer at the surface of a body over which flow takes place, based on the active change of the original motion of flow particles in close proximity to the surface. It doesn't utilized VG or an Active Hull but rather numerous sensors and vibration transmitters to alter a low volume flow. Similarly U.S. Pat. No. 5,791,275 utilizes electromagnetic tiles to alter flow at the micro level near the skin surfaces which would require a very large complex fragile system on the exterior of the craft.
Dynamic hulls or hulls with parts moving across their surface have also been explored previously. U.S. Pat. No. 6,508,188 considers a conveyer approach to “push” on fluid on a more standard above surface boat hull with obvious limitations to speed and stealth. U.S. Pat. No. 4,734,067 is closer in appearance externally to the concept described herein but it uses an auger approach or “a helical flight” to push on fluid to give an equal and opposite reaction in the forward direction. An auger or a flight is excluded from the definition of Surface Treatment used herein for two reasons. They do not satisfy the “distributed” portion of the definition because when motionless they cover little surface area as seen from above and they do not address drag. Elias-Reyes does however develop one of many possible systems to mechanically rotate a device from inside a craft that could be utilized by this invention.
U.S. Pat. No. 6,948,910 develops a class of rotor blades that mesh with flows outside the boundary layer in the axial shear plane and take advantage of some of the energies normally lost through separation of vortices on propellers or blades. Polacsek's blades make no attempt to limit the drag vortices on the skin of the hubs that employ his blades. Clearly his blades have a different purpose and would be far more fragile than the more traditional shorter Blades described herein. His devices are mentioned as they are axial flow devices and take on some of the same problems dealt with herein but further down stream and within the art of blade design. He does develop the useful concept of a “meta element” with a minute positive thrust gleaned from drag forces along his blades. Most importantly he clearly describes the difficulties and “imponderabilities” involved with a mathematical approach or modeling to complex flow problems.
Prior art also establishes a large rotating fan body with shrouds that is bow mounted that increases flows down the external surface areas of a submarine that has random surface treatment such as scales or dimples on the skin. (See U.S. Patent 20020152947) The purpose is to reduce the bow wave and he does address large portions of the external skin of the craft by energizing the boundary layer. Hilleman also gives an excellent history of prior art and the problems inherent therein. However his invention does not address the direction of bulk flow over the hull and therefore has no opportunity to create some advantage from specific VG. He would also have a very noisy system particularly if he employed the supercavity characteristics he describes.
Prior art in naval craft does utilizes boundary layer forces from vortices generated on the skin of the craft. U.S. Patent 20090250129 gives a clear account of Vortex Induced Forces and Motion (VIFM) on a bluff body. He utilizes surface roughness to produce random vortices and then captures or harness those vortices as a source of power. He is not concerned with controlled vortex generation on those surfaces but his studies do show the harnessing of useful power within vortices.
Propellers and Fixed Hulls have pressed limits so far in subsurface vessels in order to accommodate a larger faster quieter envelope that now nothing is too complicated or fragile to be overlooked. Biometrics has been explored to help with the solution through robotic fish which use a “flexible” body or hull utilizing vortices to affect greater relative mass flows than their tails alone could provide. However, the state of the art for craft utilizing vortices and flexible dynamic hulls is far from delivering large payloads under harmful conditions.
The other area of active or dynamic hulls that has been studied has a rotation on an axis perpendicular to the longitudinal or fore-aft axis and is generally meant to be a floating craft. One of the more common examples is a very large wheeled vehicle that uses the rotary motion of the tires to keep the flotation and give propulsion at the same time with an aggressive tread. More sophisticated versions can be found in US Patent 20070175380. These designs have limitations as to its velocity and effectiveness as an underwater craft.
U.S. Patent 20090200416 dealt with boundary layer propulsion and control issues on airships and did so with an eye to the needed distributed propulsion systems. It placed a “plurality of micro propellers and riblets” in the boundary layers or boundary layer separation areas but did not use a rotating hull or anything similar to accomplish the desired ends. It did mention the impracticality and implementation complexity of a great number of power sources for low powered micro propulsion units that the Active Hull contained herein is able to address.
Previous patents and literature have covered vortex generation, arrays of VG, surface treatment both random and specific, boundary layer propulsion, extracting energy from vortices, and ships with large rotating structures. But none accomplish the mission of propelling a rugged high velocity underwater craft or device utilizing boundary layer forces and distributed propulsion while avoiding the noise of cavitation.
A submersible vehicle, apparatus and method utilizing the Active Hull Platform to decrease drag and hydrodynamic noise while increasing thrust through boundary layer vortex control and distributed propulsion.
In the following detailed description of the invention, numerous specific details are provided for a thorough understanding of the invention. However, it will be appreciated by those skilled in the art that the invention may be practiced without utilizing every one of these details in any one embodiment. In addition, well-known methods, procedures, materials, components and circuitry have not been described in elaborate detail to avoid an unnecessary obscuring of the invention. Many of these “means” are described by those in “related art” and as such are included as if written herein. However enough information is given so a Craft could be built and methods could be followed using the information contained herein along with state of the art methods and materials. The reference materials included herein and simplified drawings attached hereto and made a part hereof in absence of the ability to present a working model are deemed the best way to concisely convey the substance of the invention.
For the sake of brevity much of the fluid dynamic terminology and underlying concepts are not restated herein and are well known in the art. There are words listed in the terminology section that the applicant would like to clarify or may have used differently from the art due to the uniqueness of the system and Craft. Words listed in the terminology section are capitalized when used herein including the claims section. Whenever there is a conflict between word usage in the art and the capitalized words listed in this terminology section, the definitions of words listed in TERMINOLOGY will take precedence and supersede those used in the art.
Active Hull refers to one or more powered rotating bodies, elements, shells, hulls or the like, whether that body is a Pressure Hull or a Light Hull or both of any shape, length and diameter, which rotates about a fore-and-aft axis that can be hydrodynamically or rotationally balanced. An Active Hull may cover wholly a Fixed Hull or partially, thereby exposing some elements of that non rotating entity. An Active Hull will always have Surface Treatments in Area (1) but may have either a Right Handed or Left Handed rotation (counter-clockwise or clockwise) or both as in the case of two counter-rotating Active Hulls.
Active Hull Platform is the formation and exploitation of Apparent Flows and Surface Treatment in Area (1) or Area (1) and Area (2) by utilizing an Active Hull.
Apparent Flow refers to the actual flow of fluid as seen by an incremental area on or within the embodiment or Active Hull. It is the resultant or vector sum of the rotational flows and axial fore-aft flows. For example it is the fluid as it appears to a Vortex Generator (VG) on an embodiment while the Craft is in motion.
Area (1) refers to the area that contains the external Skin of an embodiment or Active Hull, Surface Treatment if any, and the external boundary layer and the area beyond as illustrated in
Area (2) as depicted in
Blade refers to a short wing whose purpose is to interact with Apparent Flow but need not necessarily have some pitch or angle of attack to Apparent Flow. A Blade's purpose is to create thrust and is similar to traditional blades of a propeller in their design in those stations more distal from the axis of rotation. These Blades can exist in great numbers or arrays, be shorter in length, be made from more flexible materials, have little or no need for a “twist”, and when distributed in great numbers have smaller individual thrusts giving a smoother overall increased impulse.
Boundary Layer Thrust refers to forces on or near the Skin that are a result of vortices with some component of their momentum nearest the Skin in the forward direction.
Bulk Flow is fully developed stream flow and for the purposes of this application is the Apparent Flow beyond the boundary layer and shear layer flow.
Craft is the sum of all systems that make a finished independent water vessel that would include such systems required to guide, propel, and limit drag whether traditional or some embodiment of an Active Hull.
Fixed Hull is a hull, body or craft that has a general velocity only in the fore-aft plane normally against the direction of bulk fluid flow external to the craft. It refers to a hull that has no flexibility in surfaces and does not rotate. In this application a non rotating inner hull or body is an example of a Fixed Hull as is the traditional hull of a craft.
Fixed when referring to a Surface Treatment is the apposite of Variable Surface Treatment and allows for no alteration to size or position of the Surface Treatment.
Left Handed vortex refers to a vortex downstream of a Vortex Generator (VG) that has the rotation in the direction that fingers of the left hand wrap when the thumb is pointed in the direction of flow approaching the VG.
Light Hull is a hull that allows pressure to equalize between inside and external surfaces so as to avoid the structural requirements of a Pressure hull.
Pressure Hull refers to a hull that can structurally withstand subsurface pressures and is generally dry on the inside surfaces.
Right Handed vortex refers to a vortex downstream of a Vortex Generator (VG) that has the rotation in the direction that fingers of the right hand wrap when the thumb is pointed in the direction of flow approaching the VG.
Skin refers to any surface of a craft, Fixed Hull or Active Hull in Area (1) or Area (2) in contact with a fluid.
Surface Treatment refers to any surface condition or conditions whether Fixed or Variable including a plurality of various attachments, protrusions or valleys, of any size, shape, or in any combination, joined to or made a part of the Skin in Area (1) or Area (1) and Area (2). Area (1) Surface Treatment when considered collectively with all other Surface Treatment on a Craft within the Active Hull Platform must pass a functionality test of both limiting traditional skin drag in a non random fashion and increasing thrust in a distributed area over the majority of Skin area in Area (1). This restriction is not placed on Surface Treatment in Area (2) due to the unusual and controlled nature of the flows in that area.
Trapped Vortices refer to vortices kept on or near the Skin at least in part within the boundary layer by such means as corrugations, cells, chambers and differential pressures.
Variable (as apposed to Fixed) when used in connection with Surface Treatment refers to some alteration to size, shape, concavities, convexities, placement, pitch or angle of attack.
Vortex Generator(s) (VG) refers to upstream structures in Apparent Flow that create controlled vortices with specific orientation of their axis of angular momentum in the boundary layer downstream. These vortices are in contrast to random vortices originating from random skin conditions such as dimples or scales.
Referring now to the drawings to best explain the Active Hull Platform contained herein,
For simplicity in
The definition of Active Hull does not mandate physical symmetry about the fore-aft axis but this application depicts only bodies symmetrical about the fore-aft axis of rotation. However variations including such things as shapes, cut outs, Surface Treatment both Fixed and Variable, and pattern as viewed from different perspectives could be asymmetrical in appearance and still balance when rotating using hydrodynamic pressures from such things as Variable Stabilizers or rudders in combination with the balancing tubes described later. It is easy to see intuitively that any form of an Active Hull as long as it is hydrodynamically balanced at design angular velocities would satisfy the spirit of this application and thereby be included herein.
The controlled rotational or angular velocity is introduced into the embodiment as shown in
The greater the torque applied to the embodiment the greater the need for anti-torque forces to keep the Fixed Hull 105 within from rotating. The Fixed Hull could have the torque of propellers to help counter balance the torque of the embodiment in some measure. Also in Area (2) A2 described later and illustrated in
There is generally a need for ballast in underwater Craft and with higher rotational velocities of an Active Hull there comes the need for rotational balancing as well. Bearing loads would be substantially reduced if the Active Hull embodiment is balanced by a ballast and balance tube system coupled with hydrodynamic balancing using blades or rudders.
Bearing loads are both radial and axial and could be managed by purely mechanical means of roller and thrust bearings or electromagnetic bearings or some combination of the two. Both electromagnetic and mechanical bearings are well known in the art. Axial loads on thrust bearings would be reduced if there were similar thrusts provided by both the Fixed Hull and Active Hull.
This invention alters large fluid flows relative to the customary axial velocities encountered by a Fixed Hull on its external surfaces. It does so without the disadvantages of systems employing a plurality of fragile micro systems or noisy, inefficient, piping and pumping systems with large Reynolds numbers. The managed flows are a resultant of the forward velocity and specific angular velocity of an Active Hull and can be seen by Surface Treatment in Area (1) to give a distributed thrust. Area (2) may also have managed flows that will be discussed later.
Area (1) A1 as depicted in
Surface Treatment has been defined in the terminology section but it might help to clarify the definition by illustrating what is not a Surface Treatment in Area (1). Augers, flights, blades or foils are not Surface Treatment by themselves which is easily seen when motionless and viewed from above. They don't cover large portions of total skin areas of a craft and are not meant to address boundary layer conditions that are the source of skin drag. Smooth skin is an example that is not Surface Treatment if used by itself or not used collectively with other Surface Treatment because it does not address traditional skin drag and increase thrust when used with an Active Hull. Rough skin, scales or dimples may prove slightly advantageous to the formation of vortices in the boundary layer but they don't satisfy the “non random” part of the definition as they randomly energize the boundary layer and do not form vortices with a specific axis of rotational momentum to aid in thrust and limit drag. Therefore even if numerous augers or blades were placed on rough or smooth skin they do not satisfy the definition in Area (1) even though they might cover the majority of a craft.
There are three basic types of Surface Treatment as defined herein. The first general category discussed refers to devices mechanically attached to or made a part of the Skin that create vortices or are Vortex Generators (VG) and generally have a depth within the boundary layer or shear layer. The second general type of Surface Treatment is structures of or on the Skin or within the Skin itself that can absorb, maintain, amplify, limit, dampen, protect, trap or affect vortices or the forces and energies imparted by vortices. Some examples are small cells, corrugations, roughed surfaced or cilia. A third category of Surface Treatment would be those that reach into the free stream or bulk flows beyond the boundary and shear layer that have some benefit in those flows such as Blades or Blade arrays.
Benefits of the Active Hull Platform from the first category in Area (1) A1 will be focused on first with Area (2) A2 discussed later. Vortex Generators (VG) 111 are shown in
It is known in the art that generally the optimum angle of attack of VG to flow is approximately 15° as shown in
It is important then to control the angle of attack to Surface Treatment and this is best accomplished by managing Apparent Flow. Managed Apparent Flow is done by velocity censors and power control systems that maintain any desired ratio of Vθ/Vf. As shown in
Column D shows the related positive Skin forces Fx when the rotational velocity Vθ increases relative to forward velocity Vf on an embodiment as shown in Column A, Row 1 and Row 2 respectively. The constant flow direction maintains beneficial forces from vortices in the forward direction (negative drag) facilitating dispersed areas of Boundary Layer Thrust even if the forward velocity is increased, decreased or kept constant during cruise conditions.
There are numerous benefits of putting the center of effort further forward on a Craft but with the traditional fixed hull craft they must be ignored as too costly because of the increased skin drag after the forward propulsion system due to the disruption of laminar flow. Here the more forward center of effort from accumulated Boundary Layer Thrust which is the result of the sum of all the beneficial incremental forces Fx comes with an added benefit of decreasing skin drag.
Summarizing, skin drag is a result of friction and vortices formed by that friction. It is normally considered a negative force or a positive force in a negative direction which could be stated as −Fx as shown in Column A. However, the direction of −Fx can be altered with the addition of rotational flow and Surface Treatment that is introduced by the Active Hull. These tangential or repositioned flows respond to selected VG with an appropriate angle of attack to produce vortices with some incremental momentum nearest the Skin in the forward direction of the Craft to give a −(−Fx) or +Fx and Fy. Fy can be overcome by additional torque supplied by the power source to the Active Hull and not be a burden to other more traditional propulsion systems normally found in the stern.
Therefore the Active Hull Platform is utilizing the momentum forces in vortices for an incremental forward Boundary Layer Thrust which is doing far more than just energizing the boundary layer to randomly break up or slow the formation of von Karman vortices. However these specific non random vortices would additionally interfere with the formation of von Karman vortices as they are interjecting energy into the boundary layer that oppose the formation of drag causing vortices.
As the axis of angular momentum of the vortices approaches perpendicularity to the direction of forward motion, an even larger force in the forward direction of the embodiment is possible. However, as the velocity of the Craft in the forward direction is increased, the greater the need for an increased angular velocity for the Active Hull in order to preserve a constant angle of attack to the Surface Treatment without resorting to a myriad of Variable Surface Treatments.
The second category of Surface Treatment considered herein to illustrate the advantages of the Active Hull Platform are structures of the Skin or within the Skin itself that can among other things absorb, maintain, amplify, limit, dampen or affect vortices or the forces and energies imparted by vortices. Some Surface Treatment that fall into this category are surface roughness, channels, shelves, cells, tubes, concavities, convexities, and slender protuberances or cilia on the Skin that can absorb Fx and limit the effect of Fy as developed in
The example used for the purposes of this application are cilia 136 which are illustrated in
Another example is shown in
The outflow feed and return tubes port fluid by utilizing the higher ram pressures against scuppers and lower pressures affected by Bernoulli principle as shown in
The third group of Surface Treatment utilized herein to show the positive affects of the Active Hull Platform have a primary purpose enhancing thrust in the bulk flows outside the boundary layer. Although they might inadvertently affect boundary layer flow, their main purpose is to interact with bulk flows beyond the shear layer. Long flagella like whips or slender flexible even chain like protuberances that are outside the boundary layer would fall into this category but the example used herein to illustrate the advantages of this Active Hull Platform is Blades 130. They are shown in several drawings such as
Control of flow velocity in Area (1) A1 is the same for all categories of Surface Treatments. Therefore the methodology of controlling fluid vector direction and speed won't be repeated again here and can be found above as it applies to Vortex Generators.
Where VG can be placed with an angle of attack of 15° to Apparent Flow, Blades may also be placed with some angle of attack or pitch to Apparent Flow to increase mass flow and thereby increase thrust. Depending upon design criteria and acceptable hydrodynamic noise levels, Blades could alternately be placed parallel to Apparent Flow and have no angle of attack and rely solely on lift for thrust thereby limiting noise.
As can be seen in
The Active Hull Platform employs relatively short Blades or Blade arrays over large surface areas and can exploit large bulk flows over the embodiment thereby lessoning the opportunity for cavitation. A large benefit of the Active Hull Platform is that speeds in the forward direction will not have to originate solely from a centralized propulsion system. Therefore velocity will not be sacrificed in order to avoid hydrodynamic noise provided that the Blades are designed with the appropriate camber to accommodate the design flows intended or they are Variable in nature as discussed later. They may also be designed with a slight rake as shown in
If increased mass flow providing additional thrust is acceptable and desired a Blade could be designed as is known in the art that would provide same. By altering the ratio of Vθ/Vf and taking advantage of the altered Apparent Flows to the pitch angles of the Blades an increased mass flow may be produced. Once acceleration in the forward direction is completed to some new faster speed, the Craft may once again return to a ratio of Vθ/Vf that is parallel to the pitch angle of the Blades.
Shorter Blades a long distance away from the theoretical axis of rotation would allow for a very uniform structure with negligible twist required. These numerous shorter Blades would also not be subject to the large loading that centralized propeller propulsion sees and is therefore in a position to be constructed of a variety of materials that may enhance their usage further as discussed later in Variable Surface Treatments. There is also the benefit of putting the center of effort further forward on a Craft without the disadvantages of increased turbulence aft because the Blades can be mounted parallel to fluid flow and have little effect on laminar conditions especially when used in conjunction with VG that can also provide thrust and energize the boundary layer to counter coalescing drag vortices.
The larger diameter of a traditional subsurface craft the larger the form drag and skin drag. However with the larger embodiments of an Active Hull there come advantages that help nullify these such as a larger overall net thrust from the increased surface areas that provide thrust. Another advantage with increased diameters is the decreased probability of vortex momentum breakaway as the incremental surface area exposed to fluid approaches a flat plane.
Focusing now on Area (2) A2 as seen in
When fluid is allowed to flow inside so as to equalize pressure on both sides of the Active Hull, an Active Hull could be a Light Hull. The area could be closed or nearly so with negligible through flow and effectively filled with special fluids or additives to affect such properties as friction, sound attenuation and/or magnetic flux densities. Such Treatment might include surfactants, polymers, and plasma or ion production to reduce drag between the two bodies. See U.S. Pat. No. 4,812,251. With negligible through flow the constant addition of specialized additives could also be minimized or nearly eliminated.
If Area (2) had negligible axial flows or only those flows needed to equalize pressure, it would replicate closely the Couette-Taylor system (Ref: Lathrop, Fineberg, & Swinney Volume 46). With the Active Hull the outer cylinder is in rotation and is the driving cylinder rather than the inside Fixed Hull. Therefore, the centrifugal force against the driving Active Hull would increase the frictional affects and accelerate the fluid in Area (2) at an even faster rate than if the inside cylinder were the rotating force as in the Couette-Taylor system thus giving an advantage to the Active Hull.
If appropriate Surface Treatment such as cilia or surface roughness were added to surface 103 as shown in
In open through flow situations in Area (2), unstable flows continue as Reynolds numbers increase. In a negligible flow scenario in Area (2) a Light Hull at high Reynolds numbers >10 4th has great instabilities in vortices formed so as to limit their coalescing affect as those vortices become too fragmented. (Ref: Lathrop, Fineberg, & Swinney Volume 46) These Reynolds numbers are quickly and easily reached within Area (2) with negligible through flow even with low rotational velocities of an Active Hull. It is easily seen then that the flows would quickly result in no turbulent Taylor vortices between the two cylinders making it an efficient system should the rotating fluid be utilized with the Active Hull Platform and translated into linear motion with Surface Treatment such as Blades on surface 104.
The definition of Surface Treatment allows for Blades alone provided they are placed in Area (2) and not Area (1). The exploded view of
The placement of Blades in Area (2) A2 in
In Area (1) the direction of flow as seen by Surface Treatment can be controlled by managing the rotation of the embodiment and more particularly the ratio Vf/Vθ. Area (2) has the added benefit of controlling the through flow or mass flow which gives Area (2) an added degree of freedom for managing Surface Treatments and drag forces.
Area (2) has the potential of one body moving relative to another so it also has the opportunity of creating mass flows either as a positive displacement pump with one body moving axially relative to the other, or in a rotational plane as is illustrated herein with the preferred embodiment utilizing turbine fins or Blades, or both. Area (2) has the potential for combined rotational flows and fore-aft axial flows (through flow) if fluid were allowed to enter and exit the area in an appreciable manner. These increased mass flows or thrusts could easily be ported to give some measure of guidance.
Hatches could easily control the through flow In Area (2) and could be negligible, ram pressure flow, or increased flows to aid in mass flow propulsion.
Bow intakes as shown in
Surface Treatment may be either Fixed or Variable as defined herein so as to alter some aspect of their dimensionality or positioning. U.S. Pat. No. 6,427,948 illustrates a Variable Vortex Generator.
Morphing wings are well documented in the art and can include more flexible or pliable material that can morph camber by increasing or decreasing rib length of the Blade. In the case shown in
It can be seen that some modification of Surface Treatment could be advantageous particularly with guidance or acceleration in limited areas as shown by Variable Blade 139 near the bow in
Little space will be devoted to a large plurality of individually electro-mechanically controlled Variable Surface Treatment that cover great areas of a Craft because of the impractical nature of supplying power and control over that many mechanical devices in a larger Craft. However within the scope of the Active Hull Platform individually controlled Variable Surface Treatment could be accomplished with mechanical and electro-mechanical means to benefit thrust and control over the Craft such as larger variably pitched bow blades and are therefore included herein.
It's important to note that by using Apparent Flows to keep a constant flow direction, much of the need for individually controlled Variable Surface Treatment is avoided but as seen above with the example of the morphing Blade, there are Variable Surface Treatment when used with the Active Hull Platform that are practical to implement. Other morphing or changing Surface Treatment that takes advantage of fluid speeds or centrifugal forces could be a subject of future applications.
The art of vortex generation in each design is unique to that embodiment. VG placement and density is affected by such things as Reynolds number, configuration of VG including VG height and type, diameters and velocities of hulls and surrounding locations of other structures and other Surface Treatments. The Active Hull Platform is a method or system that is the amalgamation of a managed Active Hull, Surface Treatments and design criteria.
From Investigation of Vortex Generation Dayton A Griffin December 96 RNEL for non random surface VG the data shows an optimum placement for Reynolds numbers in the magnitude of E6 to be 10h where h=depth of VG and s=distance apart or spacing of VG as shown in
Although general knowledge of placement is known in the art, optimum placement of Surface Treatment is best found through experimentation on an actual Craft of similar size, speed, Skin conditions and placement of other structures that may cast a flow shadow. This can most easily be accomplished by temporary applications of arrays utilizing suction or magnetic pads containing Surface Treatments. Placement of such devises as described in U.S. Pat. No. 6,963,810 B2 on an embodiment by utilizing a quick installation and removal as described in U.S. Pat. No. 5,265,069 or the like would give an optimum placement for any given embodiment, location and Reynolds number.
Flow strength and detection using strain gauge capability will show direction and momentum intensity of vortices produced within the boundary layer as shown in
This application thus far has only illustrated the Active Hull as a Craft but it can also be used as an apparatus or device. One such apparatus or power pod can power and maintain a surface or above surface craft.
