Numerical Analysis of Aeroacoustic Noise for High-Speed Face Milling Cutters in Three Dimensional Unsteady Flow Fields

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Chunhui Ji ◽  
Zhanqiang Liu
Keyword(s):  
High Speed ◽  
Reference Frames ◽  
Acoustic Noise ◽  
Environmental Concern ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Flow Fields ◽  
Face Milling ◽  
Noise Generation ◽  
Aeroacoustic Noise

Aeroacoustic noise produced by high speed face milling cutters is a serious environmental concern. This paper develops a modeling approach to investigate the aeroacoustic noise generation and propagation by the idling face milling cutters. The approach consists of two parts: (1) an aerodynamic model for evaluating the flow fields based on the Navier–Stokes (N–S) equation and (2) an aeroacoustic model for predicting the acoustic noise by using the Ffowcs Williams and Hawkings (FW–H) equation. Both the steady mode with the multiple reference frames (MRF) model and the unsteady mode with the sliding mesh technique by introducing steady flow variables as its initial fields are simulated. The cutter gullet regions and the insert rake face regions are found to be the primary contributors in noise generation through spectral analysis of noise sources. The acoustic noise in face milling is significantly affected by the cutter diameter and the number of cutter teeth. The noise directivity is found in vertical plane, and the irregular tooth spacing can spread the maximum sound power at the rotating frequency to higher frequencies. In addition, experiments are conducted to measure the acoustic noise from two high speed milling cutters. It is found that the experimental results are generally in good agreement with the simulations.

scholarly journals Tomographic particle image velocimetry of desert locust wakes: instantaneous volumes combine to reveal hidden vortex elements and rapid wake deformation

2012 ◽  
Vol 9 (77) ◽  
pp. 3378-3386 ◽  
Author(s):  
Richard J. Bomphrey ◽  
Per Henningsson ◽  
Dirk Michaelis ◽  
David Hollis
Keyword(s):  
Particle Image Velocimetry ◽  
High Speed ◽  
Particle Image ◽  
Aerodynamic Force ◽  
Three Dimensional ◽  
Flow Fields ◽  
Diagnostic Methods ◽  
Tomographic Particle Image Velocimetry ◽  
Image Velocimetry ◽  
Spatio Temporal

Aerodynamic structures generated by animals in flight are unstable and complex. Recent progress in quantitative flow visualization has advanced our understanding of animal aerodynamics, but measurements have hitherto been limited to flow velocities at a plane through the wake. We applied an emergent, high-speed, volumetric fluid imaging technique (tomographic particle image velocimetry) to examine segments of the wake of desert locusts, capturing fully three-dimensional instantaneous flow fields. We used those flow fields to characterize the aerodynamic footprint in unprecedented detail and revealed previously unseen wake elements that would have gone undetected by two-dimensional or stereo-imaging technology. Vortex iso-surface topographies show the spatio-temporal signature of aerodynamic force generation manifest in the wake of locusts, and expose the extent to which animal wakes can deform, potentially leading to unreliable calculations of lift and thrust when using conventional diagnostic methods. We discuss implications for experimental design and analysis as volumetric flow imaging becomes more widespread.

scholarly journals The impact of pelvic lateral rotation on hindlimb kinematics and stride length in the red-legged running frog, Kassina maculata

2019 ◽  
Vol 6 (5) ◽  
pp. 190060 ◽  
Author(s):  
Amber J. Collings ◽  
Laura B. Porro ◽  
Cameron Hill ◽  
Christopher T. Richards
Keyword(s):  
High Speed ◽  
Stride Length ◽  
Reference Frames ◽  
Comparative Anatomy ◽  
Three Dimensional ◽  
Video Data ◽  
The Body ◽  
Kinematic Models ◽  
Lateral Rotation ◽  
The Impact

Some frog species, such as Kassina maculata (red-legged running frog), use an asynchronous walking/running gait as their primary locomotor mode. Prior comparative anatomy work has suggested that lateral rotation of the pelvis improves walking performance by increasing hindlimb stride length; however, this hypothesis has never been tested. Using non-invasive methods, experimental high-speed video data collected from eight animals were used to create two three-dimensional kinematic models. These models, each fixed to alternative local anatomical reference frames, were used to investigate the hypothesis that lateral rotation of the mobile ilio-sacral joint in the anuran pelvis plays a propulsive role in walking locomotion by increasing hindlimb stride length. All frogs used a walking gait (duty factor greater than 0.5) despite travelling over a range of speeds (0.04–0.23 m s −1 ). The hindlimb joint motions throughout a single stride were temporally synchronized with lateral rotation of the pelvis. The pelvis itself, on average, underwent an angular excursion of 12.71° (±4.39°) with respect to the body midline during lateral rotation. However, comparison between our two kinematic models demonstrated that lateral rotation of the pelvis only increases the cranio-caudal excursion of the hindlimb modestly. Thus, we propose that pelvic lateral rotation is not a stride length augmenting mechanism in K. maculata .

Conveying High Torque via an Efficient, High Reduction Ratio, Coaxial, Lightweight A-XYZ Transmission™

2003 ◽  
Author(s):  
Manfred R. Kuehnle
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Acoustic Noise ◽  
Three Dimensional ◽  
Rolling Contact ◽  
Manufacturing Cost ◽  
Future Goals ◽  
Machine Elements ◽  
Prime Movers ◽  
High Torque

In the past, weight and bulk of high torque gear transmissions were determined by the emphasis on lifetime durability, manufacturability, and manufacturing cost obtainable within the stress limits of classical materials when applying the rules of classical kinematics. In contrast, the Advanced XYZ Transmission (A-XYZ™) uses neither conventional materials nor classical kinematics. Instead, for the purpose of achieving load distribution over many rolling contact “teeth”, the A-XYZ transmission conveys the required torque and speed (power) via a three-dimensional path of motion which combines simultaneous vertical rotation and precessional horizontal motion of the machine elements to achieve a dynamically balanced, reversible, coaxial input/output operation. With this intellectually challenging geometric construct plus the use of new materials, the present and future goals of obtaining lightweight gearboxes, mechanical compactness, compatibility with high-speed prime movers, such as micro-turbines and small, high rpm electric motors, have been achieved. Of course, low weight and high efficiency means more mileage per liter of fuel or KWh of energy available. The low acoustic noise (no clicking teeth) represents a high quality trademark, which all competent mechanical engineers will appreciate.

Modeling and Analysis of Aerodynamic Noise in Milling Cutters

2006 ◽  
Vol 129 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Karthikeyan Sampath ◽  
Shiv G. Kapoor ◽  
Richard E. DeVor
Keyword(s):  
High Speed ◽  
Noise Exposure ◽  
Noise Spectrum ◽  
Rotational Frequency ◽  
Face Milling ◽  
Broadband Noise ◽  
Aerodynamic Noise ◽  
Noise Generation ◽  
Modeling And Analysis ◽  
Exposure Limit

Aerodynamic noise generated in high speed face milling cutters is usually much higher than the noise exposure limit set by OSHA. Experiments were conducted on two different face milling cutters to understand the aerodynamic noise generation in face milling cutters. It is observed that dipole sources of noise are most important in determining the noise generation in rotating face milling cutters. The aerodynamic noise spectrum consists of discrete tones at the rotational frequency and a broad range of higher frequencies, with the broadband spectrum contributing significantly to overall noise. A mathematical model based on the Ffowcs Williams-Hawkings Equation is used to predict (un-weighted) aerodynamic noise. The noise predicted compares well with the experimental observations. The cutter gullet shape was found to be an important factor in determining broadband noise.

Aeroacoustic noise calculations of non-compact bodies with permeable boundaries

2021 ◽  
pp. 095441002199699
Author(s):  
Fang Wang ◽  
Qiuhong Liu
Keyword(s):  
Circular Cylinder ◽  
Acoustic Noise ◽  
Three Dimensional ◽  
The Body ◽  
Integral Boundary ◽  
Aeroacoustic Noise ◽  
Naca0012 Airfoil ◽  
Number Flow ◽  
Directivity Patterns ◽  
Low Mach Number Flow

A hybrid computational aeroacoustic method with permeable boundary is developed to evaluate non-compact noise induced by low Mach number flow over arbitrarily shaped bodies. Based on Lighthill’s equation and the boundary element method, the unified integral equations are established in which the integral boundary surrounding the objects can be selected arbitrarily. Validation studies are developed for noise induced by two-dimensional NACA0012 airfoil and three-dimensional circular cylinder. For NACA0012 airfoil, the directivity patterns of calculated noise with different permeable boundaries agree well with Howe’s analytical solution for trailing edge model. The acoustic noise generated by circular cylinder has a good agreement with Revell’s experimental data and FW-H equation. It demonstrates that the noise predicted by different permeable boundary is as accurate as that calculated by the body surface.

Characteristics of a Single Sensor Fiber-Coupled 3D PIV for Reacting Flow-Fields

2021 ◽  
Author(s):  
Cal Rising ◽  
Jonathan Reyes ◽  
Kareem Ahmed
Keyword(s):  
High Speed ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Flow Fields ◽  
Velocity Fields ◽  
Diagnostic Approach ◽  
Reacting Flow ◽  
Shear Stresses ◽  
Piv Measurement ◽  
Single Sensor

Abstract Tomographic particle image velocimetry (Tomo-PIV) has become a standard tool for capturing a three-dimensional velocity fields in non-reacting flows. However, the diagnostic approach can become costly and challenging to implement when extended to applications which require high-speed cameras. This limitation has led to the use of fiber wound bundles to allow for multiple views to be captured on a single camera sensor. Additionally, employing this diagnostic approach on reacting flow fields becomes more complex as the introduction of the flame causes additional luminosity and optical distortion which impacts the particle field reconstruction. The current work seeks to validate and determine the limitations when utilizing a single sensor fiber coupled approach for capturing Tomo-PIV data on a reacting flow-field. A premixed propane (C3H8) and air Bunsen burner flame is utilized to examine if the single sensor approach can meet the parameters for acceptable reconstruction based on previous research. The resulting velocity fields are then compared to a traditional PIV measurement to assess the deviation of the single sensor approach from a standard velocimetry measurement approach. It is demonstrated that there is strong agreement between the velocity and vorticity for the average flow-fields, however when comparing the Reynolds Shear Stresses a significant deviation is revealed. The deviation is attributed to strong velocity fluctuations occurring within the instantaneous Tomo-PIV data, which creates a significant divergence between the measurement techniques on an instantaneous basis. This demonstrates that while the approach can obtain reliable velocity and vorticity statistics, there is significant limitations in calculating second-order turbulence statistics. Thus, revealing that there is a tradeoff between the ability to extract the full velocity gradient tensor and the extent of the turbulence related analysis which can be reliably performed.

The Design and Finite Element Simulation Analysis of the Tool in Milling Titanium Alloys

2013 ◽  
Vol 589-590 ◽  
pp. 373-377
Author(s):  
Cai Li Zhu ◽  
Shu Tao Huang ◽  
Li Zhou
Keyword(s):  
Finite Element ◽  
Titanium Alloys ◽  
Finite Element Simulation ◽  
High Speed ◽  
Maximum Stress ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Face Milling ◽  
Milling Cutter ◽  
Element Simulation

In this paper, considering material properties and processing characteristics of titanium alloys, the milling tool under the machining condition of large cutting depth and quasi-high speed is designed, and the face milling cutter with integral CBN inserts is developed. Then, the solid model of the CBN face-milling cutter is built by the three-dimensional modeling software Pro/E. At the same time, based on the platform of finite element simulation analysis, the deformation and stress analysis of the overall structures are carried out. It turns out that: the maximum stress of the cutter blades is not in the cutter tip region but distributed approximately along the direction of the main cutting edge, the maximum stress of the tool body is at the bottom of the groove for insert. The maximum stress acting on the wedge is at the bottom of the contact area between the wedge and the cutter body. Strength sensitive area of the clamping screw happens in the connection root. Through the static analysis, the reasonableness of structural design of the tool is evaluated theoretically.

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