Fine trimming equipment for reducing hair swing noise and design method

Abstract

The invention discloses fine trimming equipment capable of reducing hair swing noise and a design method. The fine trimming equipment comprises a suction main machine, an air pipe, a handheld suction tube, a movable shear, a fixed shear, a noise reduction and flow stabilization piece and comb teeth. The handheld suction tube is connected with the suction host through an air pipe, an air duct is arranged in the handheld suction tube, and an air inlet is formed in the side; the fixed shear and the movable shear are sequentially arranged at the bottom of the handheld suction tube; the comb teeth are vertically fixed at the lower end of the air inlet; the front end of the noise-reducing flow-stabilizing piece is fixedly connected with the front end of the handheld suction tube, and the other tail end of the noise-reducing flow-stabilizing piece is positioned in the air duct. When hair trimming is carried out, the suction host generates negative pressure, suction force is generated on hair from the air inlet of the handheld suction tube through the air pipe, the hair is bent along the air duct to be attached to the noise reduction and flow stabilization piece to form a whole, the hair and the noise reduction and flow stabilization piece form a filament, and the dimensionless incoming flow speed at the tail end of the filament is lower than a self-excitation critical value by adjusting the diameter of the noise reduction and flow stabilization piece. The filaments are in a stable state in the air duct, and self-excited vibration noise is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of hair cleaning equipment, and more specifically, relates to a fine trimming equipment and a design method for reducing hair swinging noise. Background Art

[0002] In the field of hair cleaning equipment, hair is often sucked away by the suction force generated by the suction device. This type of equipment can achieve various hair cleaning functions by matching various connectors. For example, a hair cleaning comb can be used to brush and suck away the cleaned hair, and an electric hair clipper can be used to push and suck away the hair. At present, a new fine trimming method has been designed in this field, which is connected to the suction device. It can trim and shape the hair while sucking away the cut hair. During the application of this fine trimming method, the hair is sucked into the air suction port, and after adjusting the trimming length of the hair, it is cut and sucked away. However, when adjusting the length of the hair sucked into the air suction port, the hair will hover in the air suction port, which will form self-excited vibration and generate noise (academically simplified to the problem of self-excited vibration of a flexible filament in a flow field with one end fixed and the other end free).

[0003] At present, the research on noise reduction in the field of hair cleaning equipment is mainly focused on the noise reduction of the suction fan and the main suction component, focusing on solving the noise generated by the suction motor. In the field of hair cleaning technology, there is still no technical means to solve the problem of hair fluttering in the air inlet where the air flows quickly during fine hair trimming, which causes noise. Summary of the invention

[0004] In view of the problem in the prior art that hair vibrates and thus causes noise at an air inlet where air flows rapidly, the present invention provides a fine trimming device that reduces the noise of hair swinging to solve such problem.

[0005] To achieve the above-mentioned purpose, the present invention provides a fine trimming device for reducing the noise of hair swinging, comprising: a hand-held suction cylinder, which is provided with an air duct and an air inlet on the side; a fixed shear and a movable shear arranged in sequence at the bottom of the hand-held suction cylinder; comb teeth vertically fixed at the lower end of the air inlet; and a noise reduction and flow stabilizing member, which is a rod-shaped member, the front end of which is fixedly connected to the front end of the hand-held suction cylinder and the end of which is located in the air duct; the hair is sucked into the air duct through the air inlet and bent to attach to the noise reduction and flow stabilizing member, so that the hair and the noise reduction and flow stabilizing member form a filament; by adjusting the diameter of the noise reduction and flow stabilizing member, the dimensionless incoming flow velocity at the end of the filament is lower than the self-excitation critical value, so that the filament is in a stable state in the air duct, thereby avoiding the generation of self-excited vibration noise.

[0006] Furthermore, the dimensionless incoming velocity at the end of the filament is U * , and its calculation formula is:

[0007]

[0008] Where U is the incoming flow velocity. The flow velocity U at the hair suction position of the air inlet can be calculated based on the suction component and the cross-sectional area of ​​the air inlet; ρ i is the mass per unit area of ​​the medium, the medium is air, at this time it is ρ i 1.29Kg / m 2 ; L is the length of the filament; E is the elastic modulus of the hair, which is 4.39×10 9 Pa;k i is the mixed structure coefficient, and its calculation formula is: i =((d+2nD) / d) 4 ; d is the diameter of the noise reduction and flow stabilization component; D is the hair diameter, which is 0.07 mm; n is the number of hair layers; I is the moment of inertia of the section, and its calculation formula is: I = πD 4 / 64; the self-excitation critical value is 15.

[0009] Furthermore, it also includes a suction main unit and an air duct, and the handheld suction cylinder is connected to the suction main unit through the air duct.

[0010] Furthermore, a suction component and a filter collection component are provided in the suction host; the suction component generates negative pressures of different intensities, and the hair is sucked into the filter collection component through the air duct and the handheld suction cylinder, so that the cut hair is collected in a centralized manner.

[0011] Furthermore, the handheld suction cylinder includes a connecting transition section cylinder and a suction section cylinder; the rear end of the connecting transition section cylinder is a tubular structure, the diameter of which is adapted to the air duct, and is connected to the air duct through a thread; the front end of the transition section cylinder gradually shrinks and is connected to the suction section cylinder.

[0012] Furthermore, the suction section cylinder is a shuttle-shaped structure, with an air duct connected to the air pipe inside, an air inlet connected to the air duct on the side, and an insertion hole at the front end.

[0013] Furthermore, the fixed shear is fixed to the bottom of the suction section cylinder by bolts, and its blade is located on the air inlet side.

[0014] Furthermore, the movable scissors include a blade, a handle and a pin hole; the blade and the handle are integrally formed, a pin hole is opened on the rear end of the blade, and the fixed pin passes through the pin hole to hinge the movable scissors with the fixed scissors.

[0015] According to another aspect of the present invention, there is also provided a design method for reducing hair swing noise, comprising the following steps:

[0016] S100: inserting a noise reduction and flow stabilizing component into the uniform flow field formed by the air duct, so that one end of the component is a fixed boundary condition and the other end is a free boundary condition;

[0017] S200: The hair enters the uniform flow field and is absorbed and wrapped in the noise reduction and flow stabilization parts to form filaments;

[0018] S300: Adjust the diameter of the noise reduction and flow stabilizing component so that the dimensionless incoming flow velocity U* at its end is less than the critical value to avoid the generation of self-excited vibration noise;

[0019] In step S300, the dimensionless incoming flow velocity is U*, and its calculation formula is:

[0020]

[0021] Where U is the incoming flow velocity. The flow velocity U at the hair suction position of the air inlet can be calculated based on the air volume of the suction component and the cross-sectional area of ​​the air inlet; ρ i is the mass per unit area of ​​the medium, the medium is air, at this time it is ρ i 1.29Kg / m 2 ; L is the length of the filament; E is the elastic modulus of the hair, which is 4.39×10 9 Pa;k i is the mixed structure coefficient, and its calculation formula is: i =((d+2nD) / d) 4 ; d is the diameter of the noise reduction and flow stabilization component; D is the hair diameter, which is 0.07mm; n is the number of hair layers; I is the moment of inertia of the section, and its calculation formula is: I = πD 4 / 64.

[0022] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0023] 1. The fine trimming device of the present invention generates suction on the hair coming out of the air inlet of the handheld suction tube through the air duct, and the magnetic noise reduction and flow stabilizing element has an adsorption effect on the hair with static electricity, so that the hair is bent along the air duct and attached to the noise reduction and flow stabilizing element to form a whole. The two form a filament. By adjusting the diameter of the noise reduction and flow stabilizing element, the dimensionless incoming flow velocity at the end of the filament is lower than the self-excitation critical value, so that the filament is in a stable state in the air duct, avoiding the generation of self-excited vibration noise.

[0024] 2. The fine trimming device of the present invention can be customized to design noise reduction and flow stabilizing parts for reducing the self-excited vibration noise of hair for fine trimming of different structural forms. The design method is simple, the structure is simple, the cost is low, and the noise reduction effect is excellent. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of a fine trimming device for reducing hair swinging noise according to an embodiment of the present invention;

[0026] Figure 2A bottom view of a fine trimming device for reducing hair swinging noise according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of a handheld suction tube in an embodiment of the present invention;

[0028] Figure 4 It is a schematic diagram of the structure decomposition of the handheld suction tube in an embodiment of the present invention;

[0029] Figure 5 It is a structural cross-sectional view of a handheld suction tube in an embodiment of the present invention;

[0030] Figure 6 This is a table of related parameter values ​​of dimensionless incoming flow velocity without adding noise reduction and flow stabilizing components in the embodiment of the present invention;

[0031] Figure 7 This is a numerical table of related parameters of dimensionless incoming flow velocity after adding noise reduction and flow stabilizing components in the embodiment of the present invention;

[0032] Figure 8 This is a noise comparison diagram before and after the equipment in the embodiment of the present invention adopts the noise reduction and flow stabilization component.

[0033] In all the drawings, the same reference numerals represent the same technical features, specifically: 1-suction main unit, 2-air duct, 3-handheld suction cylinder, 31-connecting transition section cylinder, 32-suction section cylinder, 321-air inlet, 322-insertion hole, 323-air duct, 4-movable shears, 41-blade, 42-handle, 43-pin hole, 5-fixed shears, 6-noise reduction and flow stabilizing part, 7-fixing pin, 8-comb teeth. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] like Figure 1-5As shown, the present invention discloses a fine trimming device for reducing hair swinging noise, comprising a suction main unit 1, an air duct 2, a hand-held suction cylinder 3, a movable shear 4, a fixed shear 5, a noise reduction and flow stabilizing member 6 and comb teeth 8. The hand-held suction cylinder 3 is connected to the suction main unit 1 through the air duct 2, and is provided with an air duct 322 therein, and an air inlet 321 is opened on the side; the fixed shear 4 and the movable shear 5 are arranged at the bottom of the hand-held suction cylinder 3 in sequence; the comb teeth 8 are vertically fixed at the lower end of the air inlet 321; the noise reduction and flow stabilizing member 6 is a magnetic rod-shaped member, the front end of which is fixedly connected to the front end of the hand-held suction cylinder 3, and the end is located in the air duct 322. When trimming hair, the suction host 1 generates negative pressure, and generates suction on the hair coming out of the air inlet 321 of the handheld suction tube 3 through the air duct 2, so that the hair is bent along the air duct 322 and attached to the noise reduction and flow stabilizing component 6 to form a whole. The two form a filament. By adjusting the diameter of the noise reduction and flow stabilizing component 6, the dimensionless incoming flow velocity at the end of the filament is lower than the self-excitation critical value, so that the filament is in a stable state in the air duct 322, avoiding the generation of self-excited vibration noise.

[0036] like Figure 1 As shown, the suction host 1 is provided with a suction component and a filter collection component; the suction component can generate negative pressures of different intensities, and the hair is sucked into the filter collection component through the air duct 2 and the handheld suction tube 3, and the cut hair is collected through the filter collection component, which can facilitate subsequent centralized removal and processing.

[0037] like Figure 2-5 As shown, the handheld suction cylinder 3 includes a connecting transition section cylinder 31 and a suction section cylinder 32; the rear end of the connecting transition section cylinder 31 is a tubular structure, and its diameter is adapted to the air duct 2, and can be connected to the air duct 2 as a whole through a thread; the front end of the transition section cylinder 31 gradually shrinks and is connected to the suction section cylinder 32 as a whole; the suction section cylinder 32 is a shuttle-shaped structure, and an air duct 323 is provided inside it to communicate with the air duct 2, an air inlet 321 is provided on the side to communicate with the air duct 323, and an insertion hole 322 is provided at the front end; by providing the air inlet 321 and the air duct 323, hair can enter the air inlet 321 under the action of negative pressure, and after the hair is cut off, it can enter the suction host 1 along the air duct 323 and the air duct 2 for filtration and centralized collection.

[0038] The comb teeth 8 are vertically fixed to the lower end of the air inlet 321 and are located on the suction section cylinder 32. They are made of plastic material and are integrally injection-molded with the handheld suction cylinder 3. They can comb the hair and adjust the length of the hair entering the air inlet 321. Furthermore, the hair is combed by the comb teeth 8 to make it smooth, and after entering the air inlet 321, it can be evenly adsorbed on the noise reduction and flow stabilizing component 6.

[0039] The fixed shears 5 are fixed to the bottom of the suction section cylinder 32 by bolts, and the blade is located at one side of the air inlet 321. After the fixed shears 5 cooperate with the movable shears 4 to cut the hair, the hair can be directly sucked in from the air inlet 321, avoiding the hair falling on the ground and avoiding the need for subsequent cleaning operations.

[0040] The movable shears 4 include a blade 41, a handle 42 and a pin hole 43; the blade 41 and the handle 42 are integrally cast, a pin hole 43 is opened on the rear end of the blade 41, and the fixed pin 7 passes through the pin hole 43 to hinge the movable shears 4 and the fixed shears 5.

[0041] The front end of the noise reduction and flow stabilizing member 6 is fixedly connected to the insertion hole 322 by interference fit or adhesive fixation, and the end thereof is located in the air duct 323, which can effectively reduce the self-excited vibration noise when the hair is sucked in. Furthermore, the noise reduction and flow stabilizing member 6 can be a rod-shaped member or other structure that conforms to fluid mechanics. According to the Bernoulli principle, the cross-section of the airflow is contracted, the flow velocity increases along the way, and the pressure decreases along the way, that is, the pressure around the noise reduction and flow stabilizing member 6 is lower than the pressure in the air duct 323, so that the hair automatically adheres to the noise reduction and flow stabilizing member 6 to form a whole, and the two form a filament.

[0042] In the embodiment of the present invention, hair is attached to the noise reduction and flow stabilizing member 6 to form a filament, and the diameter of the noise reduction and flow stabilizing member 6 is adjusted to make the dimensionless flow velocity at the end of the filament lower than the self-excitation critical value, so as to keep the filament in a stable state in the air duct 322 and avoid the generation of self-excitation vibration noise. * , and its calculation formula is:

[0043]

[0044] Where U is the incoming flow velocity. The flow velocity U at the hair suction position of the air inlet can be calculated based on the air volume of the vacuum cleaner and the cross-sectional area of ​​the air inlet; ρ i is the mass per unit area of ​​the medium, the medium is air, at this time it is ρ i 1.29Kg / m 2 ; L is the length of the filament; E is the elastic modulus of the hair, which is 4.39×10 9 Pa;k i is the mixed structure coefficient, and its calculation formula is: i =((d+2nD) / d) 4 ; d is the diameter of the noise reduction and flow stabilization component 6; D is the hair diameter, which is 0.07 mm; n is the number of hair layers; I is the moment of inertia of the section, and its calculation formula is: I = πD 4 / 64; the self-excitation critical value is 15.

[0045] The embodiment of the present invention also provides a design method for reducing hair swinging noise, comprising the following steps:

[0046] S100: inserting a noise reduction and flow stabilizing member 6 into the uniform flow field formed by the air duct 323, so that one end of the member is in a fixed boundary condition and the other end is in a free boundary condition;

[0047] S200: The hair enters the uniform flow field and is absorbed and wrapped in the noise reduction and flow stabilizing element 6 to form filaments;

[0048] S300: adjusting the diameter of the noise reduction and flow stabilizing member 6 so that the dimensionless incoming flow velocity U* at the end thereof is less than a critical value to avoid the generation of self-excited vibration noise.

[0049] In step S300, the dimensionless incoming flow velocity is U*, and its calculation formula is:

[0050]

[0051] Where U is the incoming flow velocity. The flow velocity U at the hair suction position of the air inlet can be calculated based on the air volume of the vacuum cleaner and the cross-sectional area of ​​the air inlet; ρ i is the mass per unit area of ​​the medium, the medium is air, at this time it is ρ i 1.29Kg / m 2 ; L is the length of the filament; E is the elastic modulus of the hair, which is 4.39×10 9 Pa;k i is the mixed structure coefficient, and its calculation formula is: i =((d+2nD) / d) 4 ; d is the diameter of the noise reduction and flow stabilizing element (6); D is the hair diameter, which is 0.07 mm; n is the number of hair layers; I is the cross-sectional inertia moment, which is calculated as follows: I = πD 4 / 64; the self-excitation threshold is 15.

[0052] When the above method is applied to fine trimming, the filament is hair, the fluid medium is air, and the self-excitation critical value is set to 15, that is, a noise reduction and flow stabilizing component 6 is set at the position where the hair is prone to self-excited vibration, so that the dimensionless incoming flow velocity is lower than 15, which can keep the system in a steady state and is not prone to self-excited vibration noise.

[0053] like Figure 6 As shown, in the embodiment of the present invention, when the noise reduction and flow stabilizing member 6 is not added, the following parameter values ​​can be obtained according to the relevant parameters of the fine trimming equipment:

[0054] (1) According to the air volume of the suction main unit 1 and the cross-sectional area of ​​the air inlet 321, the flow velocity U at the air inlet 321 can be calculated to be 20 m / s;

[0055] (2) The mass per unit area of ​​the medium is 1.29 for air;

[0056] (3) The length of hair inhalation is 4 cm;

[0057] (4) The diameter of hair is generally 0.04-0.09 mm, 0.07 mm is taken;

[0058] (5) The elastic modulus of hair is 4.39×10 9 Pa;

[0059] (6) The mixed structure coefficient is 1;

[0060] (7) The moment of inertia of the section is based on a cylindrical shape, I = 1.18E-18m 4 ;

[0061] Thus, the dimensionless velocity U of the hair can be obtained * =2527.04, this value is too high and it is very easy to generate self-excited vibration noise.

[0062] like Figure 7 As shown, after the noise reduction and flow stabilizing member 6 with a diameter of 1.5 mm is used for flow stabilization, the hair will flow along the noise reduction and flow stabilizing member 6 and become a whole with the noise reduction and flow stabilizing member 6, and the diameter becomes the diameter of the noise reduction and flow stabilizing member 6 plus several times the hair diameter. According to 3 layers of hair plus 6 times of hair, the filament diameter is 1.85 mm; the dimensionless velocity U is calculated. * =3.36, less than 15, the system is in a steady state, and it is not easy to generate self-excited vibration noise

[0063] like Figure 7 As shown in the figure, after the noise reduction stabilizer 6 is used for noise reduction, the noise is reduced from 62.9dB to 58.9. Compared with the 1 / 3 octave spectrum, it can be seen that before adding the stabilizer structure, there are obvious peaks at 160Hz and 315Hz, which are mainly caused by the self-excited vibration of the hair. After adding the noise reduction stabilizer 6, the noise at 160Hz and 315Hz is reduced by 9.6dB and 11.2dB respectively, and the peak is obviously eliminated.

[0064] The design method of reducing the hair self-excited vibration noise of the present invention can be customized to design a noise reduction and flow stabilizing component 6 for reducing the hair self-excited vibration noise for fine trimming of different structural forms. The design method is simple, the structure is simple, the cost is low, and the noise reduction effect is excellent.

[0065] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fine trimming device for reducing hair swinging noise, characterized in that: include: A handheld suction tube (3) is provided with an air duct (322) therein and an air inlet (321) is opened on the side; A fixed shear (4) and a movable shear (5) are sequentially arranged at the bottom of the hand-held suction tube (3); Comb teeth (8) vertically fixed at the lower end of the air inlet (321); and a noise reduction and flow stabilizing member (6) having a front end fixedly connected to the front end of the handheld suction tube (3) and a rear end located in the air duct (322), the noise reduction and flow stabilizing member being a rod-shaped member; The hair is sucked into the air duct (322) through the air inlet (321) and bent to adhere to the noise reduction and flow stabilizing member (6), so that the hair and the noise reduction and flow stabilizing member 6 form a filament. By adjusting the diameter of the noise reduction and flow stabilizing member (6), the dimensionless incoming flow velocity at the end of the filament is lower than the self-excitation critical value, so that the filament is in a stable state in the air duct (322), thereby avoiding the generation of self-excited vibration noise.

2. A fine trimming device for reducing hair swinging noise according to claim 1, characterized in that: The dimensionless incoming velocity at the end of the filament is U * , and its calculation formula is: Where U is the incoming flow velocity. The flow velocity U at the hair suction position of the air inlet can be calculated based on the air volume of the suction component and the cross-sectional area of ​​the air inlet; ρ i is the mass per unit area of ​​the medium, the medium is air, at this time it is ρ i 1.29Kg / m 2 ; L is the length of the filament; E is the elastic modulus of the hair, which is 4.39×10 9 Pa;k i is the mixed structure coefficient, and its calculation formula is: i =((d+2nD) / d) 4 ; d is the diameter of the noise reduction and flow stabilizing element (6); D is the hair diameter, which is 0.07 mm; n is the number of hair layers; I is the cross-sectional inertia moment, which is calculated as follows: I = πD 4 / 64; the self-excitation threshold is 15.

3. A fine trimming device for reducing hair swinging noise according to any one of claims 1-2, characterized in that: It also comprises a suction main unit (1) and an air duct (2), wherein the handheld suction cylinder (3) is connected to the suction main unit (1) via the air duct (2).

4. A fine trimming device for reducing hair swinging noise according to claim 3, characterized in that: The suction main unit (1) is provided with a suction component and a filter collection component; the suction component generates negative pressures of different intensities, and sucks the hair into the filter collection component through the air duct (2) and the handheld suction cylinder (3), so that the cut hair is collected in a centralized manner.

5. A fine trimming device for reducing hair swinging noise according to any one of claims 1-2, characterized in that: The handheld suction cylinder (3) comprises a connecting transition section cylinder (31) and a suction section cylinder (32); the rear end of the connecting transition section cylinder (31) is a tubular structure, the diameter of which is adapted to the air duct (2), and is connected to the air duct (2) via a thread; the front end of the transition section cylinder (31) is gradually contracted and connected to the suction section cylinder (32) as a whole.

6. A fine trimming device for reducing hair swinging noise according to any one of claims 1-2, characterized in that: The suction section cylinder (32) is a shuttle-shaped structure, and is provided with an air duct (323) inside thereof, which is connected to the air duct (2), an air inlet (321) is provided on the side thereof, which is connected to the air duct (323), and an insertion hole (322) is provided at the front end.

7. A fine trimming device for reducing hair swinging noise according to any one of claims 1-2, characterized in that: The fixed shear (5) is fixed to the bottom of the suction section cylinder (32) by means of bolts, and its blade is located on one side of the air inlet (321).

8. A fine trimming device for reducing hair swinging noise according to any one of claims 1-2, characterized in that: The movable shears (4) comprise a blade (41), a handle (42) and a pin hole (43); the blade (41) and the handle (42) are integrally formed, a pin hole (43) is provided on the rear end of the blade (41), and the fixed pin (7) passes through the pin hole (43) to hinge the movable shears (4) and the fixed shears (5).

9. A design method for reducing hair swinging noise, characterized in that: The steps include: S100: inserting a noise reduction and flow stabilizing member (6) into the uniform flow field formed by the air duct (323), so that one end of the member is in a fixed boundary condition and the other end is in a free boundary condition; S200: The hair enters the uniform flow field and is absorbed and wrapped around the noise reduction and flow stabilization component (6) to form filaments; S300: adjusting the diameter of the noise reduction and flow stabilizing member (6) so that the dimensionless incoming flow velocity U* at the end thereof is less than a critical value, thereby avoiding the generation of self-excited vibration noise; In step S300, the dimensionless incoming flow velocity is U*, and its calculation formula is: Where U is the incoming flow velocity. The flow velocity U at the hair suction position of the air inlet can be calculated based on the air volume of the vacuum cleaner and the cross-sectional area of ​​the air inlet; ρ i is the mass per unit area of ​​the medium, the medium is air, at this time it is ρ i 1.29Kg / m 2 ; L is the length of the filament; E is the elastic modulus of the hair, which is 4.39×10 9 Pa;k i is the mixed structure coefficient, and its calculation formula is: i =((d+2nD) / d) 4 ; d is the diameter of the noise reduction and flow stabilization component (6); D is the hair diameter, which is 0.07 mm; n is the number of hair layers; I is the cross-sectional inertia moment, which is calculated as follows: I = πD 4 / 64.

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