cavity

Abstract

The present invention relates to a body (2); a cavity (3) located on the body (2) capable of holding ammunition and similar payloads; a rear wall (4) being a surface on which an airflow (AF) generated as the body (2) moves leaves the cavity (3); and a base plate (5) above which the airflow (AF) moves along the cavity (3).

Description

Technical Field

[0001] This invention relates to the geometry of cavities in aerodynamic surfaces. Background Technology

[0002] When an aerodynamic surface is in motion, an airflow boundary layer forms on that surface, creating a slip layer that terminates surface continuity. In air vehicles, cavities containing landing gear, munition payloads, and similar equipment cause this surface continuity termination. The instability of the slip layer leads to vibration, acoustic, and turbulence problems within the cavity. Air vehicles face significant challenges, especially when munitions fall through high-subsonic, transonic, and supersonic flows. These unstable and robust structures forming in the flow regions can cause aerodynamic and aeroacoustic damage, potentially irreversible. Therefore, controlling the flow within the cavity can prevent this potential damage. Active and passive methods exist for controlling airflow within cavities. Passive methods operate systems without energy input. Conversely, in active methods, external energy is required to operate the system.

[0003] U.S. Patent No. US20190040883, included in the prior art, discloses modifications to the rear wall of a cavity in an aircraft to reduce vibration and noise caused by the cavity in areas such as ammunition storage and landing gear. Regarding the cavity geometry, it is mentioned that the rear wall of the cavity is made entirely convex.

[0004] In another published patent document, US2020 / 062379A1, a cavity system is disclosed. This cavity system includes: a cavity, including a cavity opening; and an acoustic reflection structure, at least partially located within the cavity. The acoustic reflection structure includes one or more acoustic reflection surfaces, wherein each acoustic reflection surface is inclined relative to the plane of the cavity opening. The one or more acoustic reflection surfaces may be arranged to reflect incident sound waves out of the cavity opening while avoiding reflection into a region at or near the front edge of the cavity. Therefore, a form of cavity sound suppression and / or control is provided to minimize acoustic energy propagating forward to interact with a shear layer near the front edge by reflecting as much acoustic energy as possible out of the cavity.

[0005] In another published patent document, US6739554B1, an acoustic resonance suppression system for an aircraft weapon bay is disclosed. The system includes a rod mounted on an extendable aircraft spoiler and spaced apart from the spoiler. The rod has a hollow core and includes a plurality of orifices arranged axially in two groups at fluid separation points. Multiple composite jets are received in the rod, each jet in fluid communication with a corresponding orifice. The jets combine to form a first disturbance element and a second disturbance element. The disturbance elements are driven out of phase in a sinusoidal manner at high frequencies by an actuator. This effectively generates a high-frequency forced airflow, which is amplified by the airflow, resulting in a violent outflow. Advantageously, this violent outflow significantly reduces acoustic resonance within the aircraft's weapon bay. Due to this system, undesirable acoustic resonance within the open weapon bay of the aircraft during flight is reduced.

[0006] Another published document, US2016 / 031386A1, discloses a cavity system for acoustic tone suppression in a cavity, wherein the system tends to increase the thickness of a shear layer 22. The cavity system includes a cavity and a plurality of rods extending away from the cavity base to a height exceeding the front edge. These rods are located downstream of and near the front edge. The rods can extend to different heights and / or be positioned longitudinally offset. When the cavity is closed, these rods can reversibly move into a configuration completely enclosed within the cavity. Flow-modifying elements can be disposed on the rods, which modify the shape of channels through the rods and / or the shape of protrusions extending from the rods. Thus, a suppression morphology is provided that disrupts the formation of large-scale eddies in the shear layer (which is part of the tone generation process) by generating multiple micro-turbulences (i.e., multiple small eddies) within the shear layer, and furthermore, the multiple micro-turbulences tend not to combine into larger turbulences. Summary of the Invention

[0007] The cavity geometry developed using this invention can reduce aerodynamic noise caused by pressure fluctuations due to high-speed airflow.

[0008] An air vehicle developed to achieve the objectives of the present invention includes: a cavity disposed on an aerodynamic surface (referred to as the body) and housing landing gear, ammunition, and similar equipment; a rear wall, the surface of which is the last surface that the airflow formed as the body moves comes into contact with after traveling along the cavity; and a floor plate, the surface forming the length of the cavity, and a boundary layer formed by the airflow on the body travels along the cavity as a slip layer above the floor plate.

[0009] The air vehicle of the present invention includes a layered reinforcement located longitudinally on the rear wall of a cavity, formed in an inclined form and positioned such that the layer extends into the cavity in a direction opposite to the airflow, and the layer is capable of reducing undesirable effects caused by airflow (such as aerodynamic noise and resonance) by widening the distance between the portion of the layer facing the floor plate toward the interior of the cavity and the floor plate itself.

[0010] In one embodiment of the invention, the air vehicle includes: a cross edge, which is the location where the rear wall of the cavity intersects with the floor plate, the rear wall being the last surface of the cavity exposed to airflow; a rear edge, which is the last portion of the cavity to encounter airflow; and an arcuate reinforcement positioned mirror-symmetrically on an axis that extends perpendicularly to the rear wall at equidistant points from the cross edge and the rear edge.

[0011] In one embodiment of the invention, the air vehicle includes a reinforcement having a curved portion toward the interior of the cavity, one edge of the reinforcement being located on a cross edge and the other edge of the reinforcement being located on a rear edge.

[0012] In one embodiment of the invention, the air vehicle includes a reinforcement with an arcuate angle determined based on a parameter obtained by making the cavity depth value proportional to the longest distance between the cavity rear wall and the layer.

[0013] In one embodiment of the invention, the air vehicle includes a reinforcement made of a piezoelectric material, which enables the generation of electrical energy by pressure and stress acting on the reinforcement.

[0014] In one embodiment of the invention, the air vehicle includes a reinforcement made of a material with a porous structure, thereby reducing the level of aerodynamic noise.

[0015] In one embodiment of the invention, the air vehicle includes a reinforcement member, which, because the reinforcement member and the layers thereon are made of a flexible material, can change the distance between the layers and the rear wall by reducing or increasing the arc angle.

[0016] In one embodiment of the invention, the air vehicle includes a reinforcement integrally formed with the rear wall of the cavity.

[0017] In one embodiment of the invention, the air vehicle includes a reinforcement that can be attached to and detached from the rear wall of the cavity.

[0018] In one embodiment of the invention, the air vehicle includes a reinforcement made of shape memory alloy, the reinforcement having: a first position I, in which, when a payload (such as landing gear or ammunition) is present in the cavity, the reinforcement has the same shape as the rear wall and thus shortens the length of the cavity by only the thickness of a material; and a second position II, in which, when the cavity cover is opened for dropping ammunition or deploying the landing gear, the reinforcement changes its shape by being triggered by a control unit to take on an arcuate shape on the rear wall, the reinforcement being switchable between the first position I and the second position II by the control unit.

[0019] In one embodiment of the invention, the air vehicle includes a reinforcement having: a third position III in which the cover of a cavity containing a payload (such as ammunition, landing gear) is closed, and the reinforcement is located on the floor and thus does not cause the length of the cavity to be shortened; and a fourth position IV in which the reinforcement is moved from the third position III to the rear wall by a robotic arm when ammunition is dropped or the landing gear is lowered by opening the cavity cover.

[0020] In one embodiment of the invention, the air vehicle includes a reinforcement having at least one heater for removing or preventing icing on aerodynamic surfaces (such as the reinforcement) due to free airflow occurring on the body. Attached Figure Description

[0021] The accompanying drawings illustrate an air vehicle implemented to achieve the objectives of the present invention, wherein, from these drawings;

[0022] Figure 1 It is a schematic diagram of an air vehicle and its cavity.

[0023] Figure 2 It is a three-dimensional view of the cavity and reinforcing components.

[0024] Figure 3 This is a schematic diagram of the cavity and reinforcing components.

[0025] Figure 4 This is a schematic diagram of the cavity and reinforcing components.

[0026] Figure 5 This is a schematic diagram of the cavity, reinforcement, and heater.

[0027] Figure 6 This is a schematic diagram of the layer, reinforcement, and control unit located in the first position I.

[0028] Figure 7 This is a schematic diagram of the layer, reinforcement, and control unit located in position II.

[0029] Figure 8 This is a schematic diagram of the reinforcement, cavity, and robotic arm in position III when a payload is present.

[0030] Figure 9 This is a schematic diagram of the reinforcement, cavity, and robotic arm located in position IV.

[0031] Reference numbers have been assigned to the various parts shown in the accompanying drawings, and the corresponding terms for these numbers are listed below.

[0032] 1. Air transportation

[0033] 2. Main body

[0034] 3. Cavity

[0035] 4. Posterior wall

[0036] 5. Base plate

[0037] 6. Layer

[0038] 7. Reinforcing components

[0039] 8. Back edge

[0040] 9. Intersecting edges

[0041] 10. Control Unit

[0042] 11. Robotic Arm

[0043] 12. Heater

[0044] AF airflow

[0045] P plane

[0046] D Depth

[0047] C length

[0048] A angle

[0049] L Height Detailed Implementation

[0050] Air vehicle 1 includes: a main body 2; a cavity 3 located on the main body 2, capable of holding munitions and similar payloads; a rear wall 4, a surface on which an airflow AF generated as the main body 2 moves leaves the cavity 3; and a floor 5, above which the airflow AF moves along the cavity 3. Figure 1 )

[0051] The air vehicle 1 of the present invention includes: at least one reinforcing member 7 having a curved layer 6 longitudinally located on the rear wall 4 and positioned to extend into the cavity 3; and layer 6 capable of reducing pressure fluctuations caused by unstable airflow AF by widening the distance between the portion of the layer 6 facing the floor 5 toward the interior of the cavity 3 and the floor 5 itself, thereby reducing noise levels. Figure 2 )

[0052] The boundary layer formed by the airflow AF on the aerodynamic surface (i.e., the so-called body 2) deteriorates as it reaches the gap in the body 2 (i.e., the so-called cavity 3) and forms a slip layer. The advance of the airflow AF in the cavity is carried by the movement of the body 2 along the bottom plate 5 of the cavity 3 and eventually contacts the rear wall 4.

[0053] By reducing the high pressure level on the rear wall 4, the aircraft 1 is able to fly in low visibility conditions, reducing the risk of radar detection, decreasing drag, reducing aerodynamic heating, enhancing the maneuverability of the air vehicle 1, and increasing the survivability and service life of the air vehicle. The pressure level is reduced by altering the geometry of the rear wall 4. This alteration of the rear wall 4 is achieved through a device attached to the rear wall 4, called a reinforcement 7, which has a layer 6. Opening the cavity 3 cover to use ammunition or similar landing gear payloads housed in the open or closed cavity 3 creates a gap in the body 2 and destabilizes the airflow AF. Therefore, there is a layer 6 located in the cavity 3 in the opposite direction to the airflow AF, which has a curved shape, is integrally formed with or detachably attached to the rear wall 4 of the cavity 3, and is located on the rear wall 4 to cover it. The distance between the portion of layer 6 facing the base plate 5 and the base plate 5 itself can increase in the direction from the rear wall 4 toward the interior of the cavity 3. Furthermore, the distance between the portion of layer 6 facing the main body 2 and the base plate 5 can also be reduced towards the rear wall 4. Because of the reinforcing member 7 of layer 6 oriented towards the interior of the cavity 3, pressure fluctuations and acoustic noise can be reduced.

[0054] In one embodiment of the invention, the air vehicle 1 includes an arcuate reinforcement 7 positioned as a mirror image of a plane P, which passes through the center of the rear wall 4 at equidistant points from the rear edge 8 and the intersecting edge 9. The rear edge is the edge through which the airflow AF exits the cavity 3, and the base plate 5 intersects the rear wall 4 at the intersecting edge. A slip layer is generated due to the deterioration of the stability of a boundary layer formed by the airflow AF on the body 2 by the cavity 3 located on the body 2. The slip layer formed by the airflow AF advancing along the base plate 5 of the cavity 3 generates undesirable acoustic noise, vibration, and pressure by impacting the rear wall 4, which is the last surface the slip layer contacts within the cavity 3. The turbulent airflow AF generated by impacting the rear wall 4 causes pressure fluctuations, thus constituting a major source of aerodynamic noise. The air vehicle includes a reinforcement 7 having a shape mirror-symmetrical with respect to the plane P, which extends perpendicularly to the rear wall 4 through an edge equidistant from the intersecting edge 9 and the rear edge 8, which are the center edges of the rear wall 4. Pressure fluctuations can be reduced through the arc-shaped reinforcement 7. Figure 4 )

[0055] In one embodiment of the invention, the air vehicle 1 includes a reinforcement 7 extending such that one end is located at the cross edge 9 and the other end is located at the rear edge 8. Since the length of the arcuate layer 6 increases as the angle A between the two fixed points increases, the resulting protrusion of the reinforcement 7 also increases. The arcuate reinforcement 7, extending between the cross edge 9 and the rear edge 8, reduces pressure fluctuations caused by airflow AF, thereby minimizing aerodynamic noise levels.

[0056] In one embodiment of the invention, the air vehicle 1 includes a reinforcement 7 formed by an angle A, which is determined based on a coefficient D / C obtained by making the depth D of the cavity 3 proportional to the length C between the layer 6 and the rear wall 4. To determine suitable parameters for altering the geometry of the rear wall 4 of the cavity 3 located on the air vehicle according to the needs and capacity of the air vehicle 1, the depth value of the cavity 3 is divided by the value corresponding to the longest distance C between the arcuate reinforcement 7 located on the rear wall 4 and the rear wall 4 itself. Using the obtained parameter D / C, the angle A of the arcuate shape to be provided for the reinforcement 7 is determined. Therefore, the arcuate reinforcement 7, which shortens the length L of the cavity 3, prevents a payload from being loaded into the cavity 3. Figure 3 )

[0057] In one embodiment of the invention, the air vehicle 1 includes a reinforcing member 7 made of a piezoelectric material capable of generating electricity through pressure acting on the layer 6. The reinforcing member 7 made of piezoelectric material generates electricity due to the mechanical effect acting on it by the airflow AF.

[0058] In one embodiment of the invention, the air vehicle 1 includes a reinforcing member 7 made of a material capable of absorbing aerodynamic noise. Because the material has a porous structure, it prevents damage to the structural components of the air vehicle 1 and absorbs the pressure formed on the reinforcing member 7.

[0059] In one embodiment of the invention, the air vehicle 1 includes a reinforcement 7 made of a flexible material capable of changing the length C between the layer 6 and the rear wall 4. Because the reinforcement 7 and the layer 6 are made of flexible material, the distance between the layer 6 and the rear wall 4 can be varied. In this way, when ammunition is present in the cavity 3 or when the landing gear is closed, the length L of the cavity 3 is slightly shorter due to the small arc angle, and when ammunition is dropped or when the landing gear is deployed, the length L of the cavity 3 becomes shorter due to the relatively large arc angle.

[0060] In one embodiment of the invention, the air vehicle 1 includes a reinforcing member 7 integrally formed with the rear wall 4. The reinforcing member 7 integrally formed with the rear wall 4 is shaped to resist high pressure levels.

[0061] In one embodiment of the invention, the air vehicle 1 includes a reinforcement 7 detachably attached to the rear wall 4. When the reinforcement 7 is not integrally formed with the rear wall 4, it is made detachably attached to the rear wall 4 to minimize effects such as vibration and aerodynamic noise caused by the high pressure level within the cavity 3. Figure 6 , Figure 7 , Figure 8 , Figure 9 )

[0062] In one embodiment of the invention, the air vehicle 1 includes: a first position I, in which, when a payload is present in the cavity 3, the reinforcement 7 has the same shape as the rear wall 4; a second position II, in which, when ammunition is dropped or when the landing gear is deployed, the arc-shaped reinforcement 7 on the rear wall 4 is moved from the first position I to the second position; and a control unit 10, which triggers a morphological change of the reinforcement 7, made of shape memory alloy, between the first position I and the second position II. The shape memory alloy exhibits a transformation between austenitic and martensitic phases under the influence of temperature and pressure. When a payload (such as ammunition, landing gear, etc.) is present in the cavity 3, the reinforcement 7, made of shape memory alloy, presents the first position I on the rear wall 4 in the shape of the rear wall 4. Because there is sufficient space in the cavity 3 when the landing gear is deployed or ammunition is dropped, the reinforcement 7, which reduces the pressure level, is heated and moved to the second position II, where the reinforcement is arc-shaped. The morphological change of the reinforcement 7 between the first position I and the second position II is controlled by the control unit 10. Figure 6 , Figure 7 )

[0063] In one embodiment of the invention, the air vehicle 1 includes: a third position III of the reinforcement 7, in which the reinforcement is located on the floor 5 when a payload is present in the cavity 3; a fourth position IV of the reinforcement 7, in which the reinforcement is moved from the third position III to the rear wall 4 when ammunition is dropped or the landing gear is deployed; and a robotic arm 11 that allows the reinforcement 7 to move from the third position III to the fourth position IV. When a payload (such as ammunition, landing gear, etc.) is present in the cavity 3 and the length L of the cavity 3 is insufficient, the position of the reinforcement 7 is changed between the rear wall 4 and the floor 5 by the robotic arm 11. The position of the reinforcement 7 on the floor 5 is referred to as the third position III, and the position of the reinforcement 7 on the rear wall 4 is referred to as the fourth position IV. Figure 8 , Figure 9 )

[0064] In one embodiment of the invention, the air vehicle 1 includes at least one heater 12 located within a reinforcement 7 and preventing icing of the reinforcement 7 by airflow AF on the body 2 and / or due to atmospheric conditions. Problems such as icing can occur on the aircraft 1 due to atmospheric conditions and airflow AF. The heater 12 is disposed within the reinforcement 7 to eliminate or prevent icing problems. The heat energy dissipated by the heater 12 ensures that icing that may occur or has already occurred on or around the reinforcement 7 can be effectively and reliably prevented and / or eliminated. Figure 5 )

Claims

1. An air transport vehicle (1), comprising: Main body (2); cavity (3), located on the main body (2), capable of placing the payload in the cavity; The rear wall (4) is a surface on which an airflow (AF) generated as the body (2) moves leaves the cavity (3); and the base plate (5) on which the airflow (AF) moves along the cavity (3) above the base plate. The feature is that at least one reinforcing member (7) has a curved layer (6) located longitudinally on the rear wall (4) and positioned to extend into the cavity (3), the layer (6) being capable of widening its orientation toward the interior of the cavity (3). The distance between a portion of the base plate (5) and the base plate (5) itself is used to reduce pressure fluctuations caused by unstable airflow (AF), thereby reducing the noise level. The reinforcing member (7), which has an arc shape, is positioned to be mirror symmetrical with respect to a plane (P) that passes through the center of the rear wall (4) at equidistant distances from the rear edge (8) and the intersecting edge (9), the rear edge being the edge through which the airflow (AF) leaves the cavity (3), and the base plate (5) and the rear wall (4) intersect each other at the intersecting edge.

2. The air transport vehicle (1) according to claim 1, characterized in that, The payload includes ammunition.

3. The air transport vehicle (1) according to claim 2, characterized in that, The reinforcement (7) extends such that one end of the reinforcement is located at the cross edge (9) and the other end of the reinforcement is located at the rear edge (8).

4. The air transport vehicle (1) according to any one of claims 1 to 3, characterized in that, The reinforcement (7) is generated by an angle (A) determined by a coefficient (D / C) obtained by making the depth (D) of the cavity (3) proportional to the length (C) between the layer (6) and the rear wall (4).

5. The air transport vehicle (1) according to claim 1, characterized in that, The reinforcing member (7) is made of a piezoelectric material that can generate electricity by pressure applied to the layer (6).

6. The air transport vehicle (1) according to claim 1, characterized in that, The reinforcing member (7) is made of a material that can absorb aerodynamic noise.

7. The air transport vehicle (1) according to claim 1, characterized in that, The reinforcing member (7) is made of a flexible material that allows the length (C) between the layer (6) and the rear wall (4) to be changed.

8. The air transport vehicle (1) according to claim 1, characterized in that, The reinforcing member (7) is integrally formed with the rear wall (4).

9. The air transport vehicle (1) according to claim 1, characterized in that, The reinforcing member (7) can be detachably attached to the rear wall (4).

10. The air transport vehicle (1) according to claim 9, characterized in that, The reinforcement (7) has a first position (I) in which, when a load is present in the cavity (3), the reinforcement has the same shape as the rear wall (4); a second position (II) in which, when the ammunition is dropped or the landing gear is deployed, the arc-shaped reinforcement (7) on the rear wall (4) is moved from the first position (I) to the second position; and a control unit (10) triggers the reinforcement (7) made of shape memory alloy to undergo a shape change between the first position (I) and the second position (II).

11. The air transport vehicle (1) according to claim 9, characterized in that, The reinforcement (7) is located in a third position (III) on the base plate (5) when there is a load in the cavity (3); the reinforcement (7) is located in a fourth position (IV) on the rear wall (4) when the ammunition is dropped or the landing gear is deployed; and the reinforcement (7) is located in a fourth position (IV) on the rear wall (4) when the ammunition is dropped or the landing gear is deployed; and the reinforcement (7) is located in a fourth position (IV) on the base plate (5) on the base plate (3) on the base plate (5) on the base plate (5) on the base plate (5) on the base plate (5) on the base plate (5) on the base plate (6) on the base plate (7) on the base plate (7) on the base plate (7) on the base plate (7) on the base plate (7) on the base plate (7) on the base plate (7) on the base plate (7) on the base plate (7) on the base plate (7) on the base plate (8 ...8) on the base plate (7) on the base plate (8) on the base plate (7) on the base plate (8) on the base plate (7) on 12. The air transport vehicle (1) according to claim 1, characterized in that, At least one heater (12) is located in the reinforcement (7) and prevents the reinforcement (7) from icing by the airflow (AF) on the body (2) and / or due to atmospheric conditions.

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