Experimental Study of the Concave Bionic Drag Reduction Needles

2013 ◽  
Vol 461 ◽  
pp. 702-706
Author(s):  
Ji Yue Wang ◽  
Qian Cong
Keyword(s):  
Drag Reduction ◽  
Reduction Rate ◽  
Outer Wall ◽  
Comparative Test ◽  
Point Of View ◽  
National Standard ◽  
Reduction Mechanism ◽  
Laser Material ◽  
Maximum Drag Reduction ◽  
Smooth Design

In this paper, we have started from the point of view of bionics, doing surface bionic non-smooth design at the standard No.16 animal syringe needles. Then treating the concave as the bionic unit, we worked out the concave bionic drag reduction needles by use of the laser material remove processing means. In accordance with the national standard on the injection drag test of disposable needles, we did the puncture drag comparative test of the smooth needles and the bionic needles, getting the correspondence relationship between the drag reduction rate and the bionic unit parameters. We found that the maximum drag reduction rate up to 44.05%, and it appeared when the concave interval was 0.9mm and the concave diameter was 0.09mm. Then through discussing the drag reduction mechanism of the bionic needles, we knew that the bionic units reduced the actual contact area between the needle outer wall and the simulation skin, and it was the main reason of bionic needles puncture drag decreases.

Drag Reduction Study about Bird Feather Herringbone Riblets

2013 ◽  
Vol 461 ◽  
pp. 201-205 ◽  
Author(s):  
Hua Wei Chen ◽  
Fu Gang Rao ◽  
De Yuan Zhang ◽  
Xiao Peng Shang
Keyword(s):  
Drag Reduction ◽  
Structural Parameters ◽  
Reduction Rate ◽  
Reduction Mechanism ◽  
Surface Drag ◽  
Flight Feather ◽  
Hollow Shaft ◽  
Smooth Edge ◽  
Bird Feather ◽  
Wild Goose

Flying bird has gradually formed airworthy structures e.g. streamlined shape and hollow shaft of feather to improve flying performance by millions of years natural selection. As typical property of flight feather, herringbone-type riblets can be observed along the shaft of each feather, which caused by perfect alignment of barbs. Why bird feather have such herringbone-type riblets has not been extensively discussed until now. In this paper, microstructures of secondary feathers are investigated through SEM photo of various birds involving adult pigeons, wild goose and magpie. Their structural parameters of herringbone riblets of secondary flight feather are statistically obtained. Based on quantitative analysis of feathers structure, one novel biomimetic herringbone riblets with narrow smooth edge are proposed to reduce surface drag. In comparison with traditional microgroove riblets and other drag reduction structures, the drag reduction rate of the proposed biomimetic herringbone riblets is experimentally clarified up to 15%, much higher than others. Moreover, the drag reduction mechanism of herringbone riblets are also confirmed and exploited by CFD.

scholarly journals An investigation on the drag reduction performance of bioinspired pipeline surfaces with transverse microgrooves

2020 ◽  
Vol 11 ◽  
pp. 24-40 ◽  
Author(s):  
Weili Liu ◽  
Hongjian Ni ◽  
Peng Wang ◽  
Yi Zhou
Keyword(s):  
Numerical Simulation ◽  
Drag Reduction ◽  
Pressure Loss ◽  
Fluid Transport ◽  
Reduction Rate ◽  
Orthogonal Analysis ◽  
Maximum Drag Reduction ◽  
Reduction Effect ◽  
Save Energy ◽  
Microgrooved Surface

A novel surface morphology for pipelines using transverse microgrooves was proposed in order to reduce the pressure loss of fluid transport. Numerical simulation and experimental research efforts were undertaken to evaluate the drag reduction performance of these bionic pipelines. It was found that the vortex ‘cushioning’ and ‘driving’ effects produced by the vortexes in the microgrooves were the main reason for obtaining a drag reduction effect. The shear stress of the microgrooved surface was reduced significantly owing to the decline of the velocity gradient. Altogether, bionic pipelines achieved drag reduction effects both in a pipeline and in a concentric annulus flow model. The primary and secondary order of effect on the drag reduction and optimal microgroove geometric parameters were obtained by an orthogonal analysis method. The comparative experiments were conducted in a water tunnel, and a maximum drag reduction rate of 3.21% could be achieved. The numerical simulation and experimental results were cross-checked and found to be consistent with each other, allowing to verify that the utilization of bionic theory to reduce the pressure loss of fluid transport is feasible. These results can provide theoretical guidance to save energy in pipeline transportations.

Effect of Bionic Concave Surface to the Drag Reduction Performance of Cylinder Sealing Ring

2014 ◽  
Vol 1055 ◽  
pp. 152-156 ◽  
Author(s):  
Gang Zhao ◽  
Fang Li ◽  
Wei Xin Liu ◽  
Jian Ying Zhao ◽  
Hong Shi Bi
Keyword(s):  
Drag Reduction ◽  
Reduction Rate ◽  
Cylinder Block ◽  
Lubricating Oil ◽  
Concave Surface ◽  
Movement Speed ◽  
Piston Velocity ◽  
Friction Resistance ◽  
Sealing Ring ◽  
Maximum Drag Reduction

According to the problem of large friction resistance exists between the sealing ring and the cylinder block when the piston cylinder works, the drag reduction technology of bionic concave surface was applied in the sealing ring. By building a drag reduction motion model of sealing ring with concave surface of triangular arrangement, the effect of drag reduction performance decided by concave diameter and piston velocity was studied with the method of numerical simulation. The results show that: when the piston velocity is fixed, the maximum drag reduction rate can be achieved with the concave diameter is 1.5mm, and the maximum drag reduction rate is 15.72%. Meanwhile when the diameter of the concave is fixed, the drag reduction rate increased gradually with the increase of initial speed, the drag reducing effect is best at the speed of 0.6m/s. In the process of piston movement, lubricating oil in concave shakes, and makes the lubricating oil flow to the inside wall of cylinder, which play the role of lubrication, so as to achieve the effect of reducing friction and increasing the movement speed of piston.

LDV Measurement of Turbulent Pipe Flow With Traveling Wavy Elastic Wall for Drag Reduction

2019 ◽  
Author(s):  
Seiya Nakazawa ◽  
Takaaki Shimura ◽  
Akihiko Mitsuishi ◽  
Kaoru Iwamoto ◽  
Akira Murata
Keyword(s):  
Drag Reduction ◽  
Pipe Flow ◽  
Reduction Rate ◽  
Streamwise Velocity ◽  
Turbulent Pipe Flow ◽  
Deformation Control ◽  
Wall Deformation ◽  
Maximum Drag Reduction ◽  
Reduction Effect ◽  
Ldv Measurement

Abstract Drag reduction effect by traveling wavy wall deformation control in turbulent pipe flow was experimentally investigated. From the visualization, we confirmed the downstream traveling wave although it was not uniform in the circumferential direction. When the frequency is 110 Hz, the wall deformation amplitude and the wavelength indicated that the effective values for drag reduction. The wavespeed is approximately effective values for drag reduction. As a result, the maximum drag reduction rate of 6.8 % is obtained. The result of a LDV measurement shows that the mean streamwise velocity gradient decreased near the wall by the control, which leads to drag reduction.

scholarly journals Investigation of the Turbulent Drag Reduction Mechanism of a Kind of Microstructure on Riblet Surface

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Mingrui Ao ◽  
Miaocao Wang ◽  
Fulong Zhu
Keyword(s):  
Drag Reduction ◽  
Three Dimensional ◽  
Reduction Rate ◽  
Water Area ◽  
Reduction Mechanism ◽  
Surface Drag ◽  
Groove Surface ◽  
Turbulent Drag ◽  
Micro Structures ◽  
Riblet Surface

With the k-ε renormalization group turbulence model, the drag reduction mechanism of three- dimensional spherical crown microstructure of different protruding heights distributing on the groove surface was studied in this paper. These spherical crown microstructures were divided into two categories according to the positive and negative of protruding height. The positive spherical crown micro-structures can destroy a large number of vortexes on the groove surface, which increases relative friction between water flow and the groove surface. With decreasing the vertical height of the spherical crown microstructure, the number of rupture vortexes gradually decreases. Due to the still water area causes by the blocking effect of the spherical crown microstructure, it was found that the shear stress on the groove surface can be reduced, which can form the entire drag reduction state. In another case, the spherical crown microstructures protrude in the negative direction, vortexes can be generated inside the spherical crown, it was found that these vortexes can effectively reduce the resistance in terms of pressure and friction. In a small volume, it was shown that the surface drag reduction rate of spherical crown microstructures protrudes in negative directions can be the same as high as 24.8%.

scholarly journals Investigation on drag reduction performance of pipeline with bioinspired microgrooved surface

2019 ◽  
Author(s):  
Weili Liu ◽  
Hongjian Ni ◽  
Peng Wang ◽  
Yi Zhou
Keyword(s):  
Numerical Simulation ◽  
Drag Reduction ◽  
Pressure Loss ◽  
Fluid Transport ◽  
Fluid Dynamic ◽  
Reduction Rate ◽  
Orthogonal Analysis ◽  
Maximum Drag Reduction ◽  
Reduction Effect ◽  
Microgrooved Surface

Novel surface morphology of pipeline with transverse microgrooves was proposed for reducing the pressure loss of fluid transport. Numerical simulation and experimental research efforts were undertaken to evaluate the drag reduction performance of bionic pipeline. The computational fluid dynamic calculation, using SST κ-ω turbulent model, shown that the “vortex cushioning effect” and “driving effect” produced by the vortexes in the microgrooves were the main reason for the drag reduction. The shear stress of the microgrooved surface was reduced significantly owing to the decline of the velocity gradient; then bionic pipeline achieved drag reduction effect in the pipe and concentric annulus flow. The primary and secondary order of effect on the drag reduction and optimal microgroove geometric parameters were obtained by orthogonal analysis method. The comparative experiments were conducted in a water tunnel, and a maximum drag reduction rate of 3.21% was achieved. The numerical simulation and experimental results were cross-checked and consistent with each other to verify that the utilization of bionic theory to reduce the pressure loss of fluid transport is feasible. Results can provide theoretical guidance for the energy saving of pipeline transportation.

scholarly journals Study on the Drag Reduction Characteristics of the Surface Morphology of Paramisgurnus dabryanus Loach

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1357
Author(s):  
Liyan Wu ◽  
Jiaqi Wang ◽  
Guihang Luo ◽  
Siqi Wang ◽  
Jianwei Qu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Drag Reduction ◽  
Reduction Rate ◽  
Underwater Vehicles ◽  
Flow Channel ◽  
Numerical Control ◽  
Reduction Mechanism ◽  
Paramisgurnus Dabryanus ◽  
Reduction Characteristics

The drag reduction design of underwater vehicles is of great significance to saving energy and enhancing speed. In this paper, the drag reduction characteristics of Paramisgurnus dabryanus loach was explored using 3D ultra-depth field microscopy to observe the arrangement of the scales. Then, a geometric model was established and parameterized. A simulated sample was processed by computer numerical control (CNC) machining and tested through using a flow channel bench. The pressure drop data were collected by sensors, and the drag reduction rate was consequently calculated. The test results showed that the drag reduction rate of a single sample could reach 23% at a speed of 1.683 m/s. Finally, the experimental results were verified by numerical simulation and the drag reduction mechanism was explored. The boundary layer theory and RNG k-ε turbulence model were adopted to analyze the velocity contour, pressure contour and shear force contour diagrams. The numerical simulation results showed that a drag reduction effect could be achieved by simulating the microstructure of scales of the Paramisgurnus dabryanus loach, showing that the results are consistent with the flow channel experiment and can reveal the drag reduction mechanism. The bionic surface can increase the thickness of boundary layer, reduce the Reynolds number and wall resistance. The scales disposition of Paramisgurnus dabryanus loach can effectively reduce the surface friction, providing a reference for future research on drag reduction of underwater vehicles such as ships and submarines.

Research on Drag Reduction Performance of Bionic Shark Gill Jet Surface

2014 ◽  
Vol 654 ◽  
pp. 57-60 ◽  
Author(s):  
Zhao Gang ◽  
Fang Li ◽  
Wei Xin Liu ◽  
Ming Ming Liu ◽  
Hong Shi Bi
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Drag Reduction ◽  
Fluid Velocity ◽  
Reduction Rate ◽  
Frictional Resistance ◽  
Normal Velocity ◽  
Main Field ◽  
Maximum Drag Reduction ◽  
Pressure Resistance

According to the problem of bionic shark gill jet can reduce friction on shark surface, a model of bionic jet surface was established based on shark surface was analyzed by measurements, and its numerical simulation was processed by using RNG k-ε turbulence model. The results show that: the gill jet can reduce frictional resistance on shark surface, and the best drag reduction can be got when the speed of main field is 5m/s, furthermore the maximum drag reduction rate can be up to 17.15%. The pressure of jet hole upstream is reduced which due to the barrier to the facing fluid by the jet, so that the pressure resistance of jet surface is reduced as well. Besides, jet fluid is blocked in the boundary layer by mainstream fluid, which caused the fluid velocity of jet hole downstream is reduced, the thickness of boundary layer is increased, and the normal velocity gradient of wall is reduced, so as to achieve the effect of drag reduction.

scholarly journals Understanding of remora's “hitchhiking” behaviour from a hydrodynamic point of view

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yunxin Xu ◽  
Weichao Shi ◽  
Abel Arredondo-Galeana ◽  
Lei Mei ◽  
Yigit Kemal Demirel
Keyword(s):  
Boundary Layer ◽  
Drag Reduction ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Reduction Rate ◽  
Adverse Pressure Gradient ◽  
Point Of View ◽  
The Body ◽  
Hydrodynamic Characteristics ◽  
Symbiotic Relationships

AbstractSymbiotic relationships have developed through natural evolution. For example, that of the remora fish attached to the body of a shark. From the remora’s perspective, this could be associated to an increased hydrodynamic efficiency in swimming and this needs to be investigated. To understand the remora's swimming strategy in the attachment state, a systematic study has been conducted using the commercial Computational Fluid Dynamics (CFD) software, STAR-CCM + to analyse and compare the resistance characteristics of the remora in attached swimming conditions. Two fundamental questions are addressed: what is the effect of the developed boundary layer flow and the effect of the adverse pressure gradient on the remora’s hydrodynamic characteristics? According to the results, the resistance of the remora can generally be halved when attached. Besides, the results have also demonstrated that the drag reduction rate increases with the developed boundary layer thickness and can be estimated using the boundary layer thickness ratio and velocity deficit. The paper demonstrates that the most frequent attachment locations are also the areas that provide the maximum drag reduction rate.

scholarly journals Global effect of local skin friction drag reduction in spatially developing turbulent boundary layer

2016 ◽  
Vol 805 ◽  
pp. 303-321 ◽  
Author(s):  
A. Stroh ◽  
Y. Hasegawa ◽  
P. Schlatter ◽  
B. Frohnapfel
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Drag Reduction ◽  
Control Region ◽  
Reduction Rate ◽  
Wall Turbulence ◽  
Local Skin ◽  
Control Schemes ◽  
Local Skin Friction ◽  
Friction Drag Reduction

A numerical investigation of two locally applied drag-reducing control schemes is carried out in the configuration of a spatially developing turbulent boundary layer (TBL). One control is designed to damp near-wall turbulence and the other induces constant mass flux in the wall-normal direction. Both control schemes yield similar local drag reduction rates within the control region. However, the flow development downstream of the control significantly differs: persistent drag reduction is found for the uniform blowing case, whereas drag increase is found for the turbulence damping case. In order to account for this difference, the formulation of a global drag reduction rate is suggested. It represents the reduction of the streamwise force exerted by the fluid on a plate of finite length. Furthermore, it is shown that the far-downstream development of the TBL after the control region can be described by a single quantity, namely a streamwise shift of the uncontrolled boundary layer, i.e. a changed virtual origin. Based on this result, a simple model is developed that allows the local drag reduction rate to be related to the global one without the need to conduct expensive simulations or measurements far downstream of the control region.

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