A method to predict the flow-induced noise of an open cavity of a complex geometry

2021 ◽  
Vol 263 (5) ◽  
pp. 1253-1260
Author(s):  
Tingsheng Zhong ◽  
Cheng Yang
Keyword(s):  
Shear Flow ◽  
Complex Geometry ◽  
Fluid Dynamic ◽  
Linear Part ◽  
Open Cavity ◽  
Hydrodynamic Mode ◽  
Computation Efficiency ◽  
Flow Past ◽  
Sound Theory ◽  
Cfd Method

Shear flow past a cavity involves a complex fluid dynamic process. Of vital importance is the occurrence of self-sustained oscillations that give rise to tones and the amplitudes of which may be further amplified if the hydrodynamic mode is coupled with the cavity mode. Extensive efforts have been made to investigate the mechanisms of such a simple yet compelling system as well as to predict the noise generated, while most of them are focused on geometry of rectangular shape. For an irregular shaped cavity, numerical methods are usually used which are computationally expensive. A method is developed to predict the tones generated by the shear flow past an open cavity of a complex geometry. In view of the feedback process involved within the system, a describing-function method decomposing the system into a non-linear part and a linear part is used. The linear description function is established by the patch mobility method where the transfer function between patches is extracted from finite element results, while the nonlinear description function is established based on the vortex sound theory. The proposed method showed a superb computation efficiency over CFD method and its accuracy was justified by comparing with the results of public literature.

scholarly journals Simulation of Flexible Fibre Particle Interaction with a Single Cylinder

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 191
Author(s):  
Naser Hamedi ◽  
Lars-Göran Westerberg
Keyword(s):  
Reynolds Number ◽  
Shear Flow ◽  
Fibre Orientation ◽  
Flow Direction ◽  
Particle Interaction ◽  
Orientation Angle ◽  
Factors Affecting ◽  
Single Cylinder ◽  
Flow Past ◽  
Fibre Suspension

In the present study, the flow of a fibre suspension in a channel containing a cylinder was numerically studied for a very low Reynolds number. Further, the model was validated against previous studies by observing the flexible fibres in the shear flow. The model was employed to simulate the rigid, semi-flexible, and fully flexible fibre particle in the flow past a single cylinder. Two different fibre lengths with various flexibilities were applied in the simulations, while the initial orientation angle to the flow direction was changed between 45° ≤ θ ≤ 75°. It was shown that the influence of the fibre orientation was more significant for the larger orientation angle. The results highlighted the influence of several factors affecting the fibre particle in the flow past the cylinder.

scholarly journals The Design and Implementation of Fan Chips as Cooling for Milling Process on Aluminum Alloy 5086 to Increase Tool Life

2021 ◽  
Vol 2 (1) ◽  
pp. 29-42
Author(s):  
Agus Sifa ◽  
Dedi Suwandi ◽  
Tito Endramawan ◽  
Alam Aulia Rachman
Keyword(s):  
Aluminum Alloy ◽  
Tool Life ◽  
Experimental Testing ◽  
Fluid Dynamic ◽  
Milling Process ◽  
Machining Process ◽  
Central Character ◽  
Spindle Rotation ◽  
Cfd Method ◽  
Increase Tool Life

In the metal machining process, especially in the milling process, the parameters that affect the quality milling process results are cooling media because it affects the tool life used. This paper aims to determine the performance of using fan chips as the coolant in the dry milling process area. The method used is the computational fluid dynamic (CFD) method and the experimental milling process on a workpiece made from aluminum alloy 5086. In experimental testing using a variation of the milling machine spindle rotation. The simulation test results on the fluid flow character on fan chips with a protector producing a central character with a small area. In contrast, fan chips without a protector make a central character with a broader area. The wind speed data in simulation testing and experimental testing produced the same trend graph. The results of the performance of fan chips after experimented with variations in spindle rotation, cooling process on area occurs when the motor spindle rotates above 1120 Rpm on the fan chips with a protector, and the engine spindle rotates above 770 Rpm on the fan chips without a protector. The effect of fan chips on tool life affects increasing tool life by 8 minutes on installing fan chips with a protector and increasing tool life by 12 minutes on installing fan chips without a protector.

scholarly journals Boundary shear flow past a cylinder near a wall

2019 ◽  
Vol 92 ◽  
pp. 101923 ◽  
Author(s):  
L.F. Chen ◽  
G.X. Wu
Keyword(s):  
Shear Flow ◽  
Boundary Shear ◽  
Flow Past ◽  
Flow Past A Cylinder

Computational study of the cavity flow over sharp nose cone in supersonic flow

2020 ◽  
Vol 31 (06) ◽  
pp. 2050079 ◽  
Author(s):  
F. Pish ◽  
Tran Dinh Manh ◽  
M. Barzegar Gerdroodbary ◽  
Nguyen Dang Nam ◽  
Rasoul Moradi ◽  
...  
Keyword(s):  
Computational Study ◽  
Fluid Dynamic ◽  
Thermal Characteristic ◽  
Main Body ◽  
Cavity Depth ◽  
Nose Cone ◽  
Sst Turbulence Model ◽  
Mach 3 ◽  
Cfd Method ◽  
Supersonic Vehicles

Heat and drag reduction on the nose cone is a significant issue for increasing the speed of the supersonic vehicles. In this paper, computational fluid dynamic method is applied to investigate the thermal and drag coefficient on the sharp nose cone with different cavity shapes. In order to simulate our model, the CFD method with SST turbulence model is applied to study the flow feature and temperature distribution in the vicinity of the nose body. The effect of depth and length of the cavity on the thermal characteristic of the nose cone is comprehensively investigated. In addition, the influence of the number of the cavity in the thermal performance of the main body is studied. According to our results, increasing the length of the cavity highly efficient for the reduction of the drag at Mach = 3. As the Mach number is increased to 3, the number of the cavity becomes a significant role and it is observed that case 9 with four cavities is more efficient. Obtained results also show that increasing the cavity depth declines the temperature on the main body. Our findings confirm that the main source of the expansion is the edge of the cavity.

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