Numerical Simulation of Two-Dimensional Acoustic Liners with High-Speed Grazing Flow

AIAA Journal ◽  
2011 ◽  
Vol 49 (2) ◽  
pp. 365-382 ◽  
Author(s):  
Qi Zhang ◽  
Daniel J. Bodony
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Two Dimensional ◽  
Acoustic Liners ◽  
Grazing Flow

ON DESIGNING IMPEDANCE TUBE WITH GRAZING FLOW

Akustika ◽  
2021 ◽  
pp. 80
Author(s):  
Vadim Palchikovskiy ◽  
Igor Khramtsov ◽  
Aleksander Kuznetsov ◽  
Victor Pavlogradskiy
Keyword(s):  
Numerical Simulation ◽  
Analytical Solutions ◽  
Gas Dynamics ◽  
Aircraft Engine ◽  
Design Parameters ◽  
Experimental Setup ◽  
Structural Units ◽  
Impedance Tube ◽  
Acoustic Liners ◽  
Grazing Flow

The article considers the general issues arising in designing the experimental setup “Impedance tube with grazing flow”, the main structural units of the setup, and their purpose. It is given the basic requirements to be provided by the setup when testing samples of acoustic liners used in an aircraft engine. The choosing of the design parameters of the setup is based on the analysis of the known analytical solutions of the acoustics and gas dynamics, and on the numerical simulation of the grazing flow in the impedance tube.

Comparisons Between Measured and Calculated Stall Development in Four High-Speed Multi-Stage Compressors

1997 ◽  
Author(s):  
A. A. J. Demargne ◽  
J. P. Longley
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Development Process ◽  
Rotating Stall ◽  
Two Dimensional ◽  
Stall Inception ◽  
Mass Injection ◽  
Multi Stage ◽  
Design Speed

In this paper the development of rotating stall in four different high-speed multi-stage compressors is investigated using a numerical simulation. Below 90 per cent of design speed the model calculates well the two-dimensional moderate to long lengthscale development of rotating stall, irrespective of the lengthscale and form of the stall inception mechanism. At higher operating speeds the model is less reliable, providing better comparisons for those compressors which exhibited modal rather than spike stall inception. The model is also used to investigate the feasibility of actively controlling the stall development process in a compressor. The conclusions reached are that mass injection and removal is far more effective than varying the blade stagger angles and that sensors must be upstream of actuators.

A flow and acoustic facility for characterization of liner and meta-acoustic surfaces under grazing flow condition

2021 ◽  
Vol 263 (3) ◽  
pp. 3187-3193
Author(s):  
Wei Yi ◽  
Jingwen Guo ◽  
Yi Fang ◽  
Renhao Qu ◽  
Siyang Zhong ◽  
...  
Keyword(s):  
Flow Field ◽  
Cross Section ◽  
High Speed ◽  
Transmission Loss ◽  
Static Condition ◽  
Flow Speed ◽  
Settling Chamber ◽  
Acoustic Liners ◽  
Diagnostic Facility ◽  
Grazing Flow

The Hong Kong University of Science and Technology (HKUST) has designed and assembled a new facility, a grazing flow tube, for aeroacoustic characteristics measurement of acoustic liners, e.g. transmission loss, impedance, etc., under a high-speed grazing flow. The cross-section of the test section of the tube has a dimension of 50 mm × 50 mm, and the grazing flow speed can be up to 0.3 Ma. A settling chamber, a long-enough flow development section and a multi-stage anechoic termination are adopted to ensure the high-quality flow field and acoustic field. This paper presents the detailed designs of the key components of the facility, as well as the calibrations of the velocity profile in a series of cross-section surfaces of the duct along the streamwise direction and sound pressure distributions in the axial and circumferential directions. Pitot tube, Hotwire and PIV are used to obtain the flow field measurement results. The overall performance of the diagnostic facility is verified by comparing the impedance results of acoustic liners acquired from an impedance tube under the static condition and the theoretical variation of axial wavenumber with Ma number under the grazing flow.

Numerical Modeling of Kites for Power Generation

2014 ◽  
Author(s):  
Alireza Mahdavi Nejad ◽  
David J. Olinger ◽  
Gretar Tryggvason
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
High Speed ◽  
Stokes Equations ◽  
Second Order ◽  
Staggered Grid ◽  
Immersed Boundary ◽  
Uniform Mesh ◽  
Two Dimensional ◽  
Time Step

A computational model of a massless kite that produces power in an airborne wind energy system (AWE) is presented. AWE systems use tethered kites at high altitudes to extract energy from the wind, and are being considered as an alternative to wind turbines since the kites can move in high-speed cross-wind motions over large swept areas to increase power production. In our model the kite completes successive power-retraction cycles where the kite angle of attack is altered as required to vary the resultant aerodynamic forces on the kite. The numerical simulation models the flow field in a two-dimensional domain near the flexible kite by solving the full Navier-Stokes equations. Eulerian grid points for the flow domain together with a Lagrangian representation of the kite are employed. The flow field is determined through a second-order finite difference projection method using a non-uniform mesh on a staggered grid. A corrector-predictor technique is employed to ensure the second-order accuracy in time of the numerical simulation. The two-dimensional kite shape is modeled as a slightly cambered immersed boundary that evolves with the flow. The flexible kite surface is modeled with a set of linear springs following Hooke’s law. The unstretched length of each elastic tether at a given time step is controlled using periodic triangular wave shapes to achieve the required power-retraction phases. A study was conducted in which the wave shape amplitude, frequency, and phase (between two tethers) was adjusted to achieve a suitably high net power output with very good agreement to predictions for Loyd’s simple kite in two-dimensional motion. Aerodynamic coefficients for the kite, tether tensions, tether reel-out and reel-in speeds, and vorticity flowfields in the kite wake are also determined.

Numerical simulation of high-speed civil transport inlet operability with angle of attack

AIAA Journal ◽  
1998 ◽  
Vol 36 ◽  
pp. 1223-1229
Author(s):  
Ge-Cheng Zha ◽  
Doyle Knight ◽  
Donald Smith ◽  
Martin Haas
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Angle Of Attack
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