Physical Insight of the Source Data of a Two-Port Acoustic Source Model

2010 ◽  
Vol 44-47 ◽  
pp. 3413-3417
Author(s):  
Bin Zhang ◽  
Xue Jun Liu ◽  
Rui Xiang Song ◽  
Bin Liu ◽  
Tao Feng
Keyword(s):  
Boundary Condition ◽  
External Source ◽  
Source Model ◽  
State Equation ◽  
Acoustic Source ◽  
Theoretical Derivation ◽  
Acoustic Boundary Condition ◽  
Source Data ◽  
Physical Insight ◽  
Full Absorption

The physical insight of the source data of two-port acoustic source model for a duct is studied in theoretical, experimental and numerical aspects respectively. Under the ideal acoustic boundary condition of full absorption at the duct ends, the state equation of two-port acoustic source model is discussed, and the physical insight of the source data is obtained through theoretical derivation. The experimental model of two-port acoustic source is established, and the source data have been measured by the method “with an external source”. The physical meaning of source data has been demonstrated through the experimental method. The numerical simulating model for the experiment system is built, and the source data obtained numerically are compared with those measured experimentally for research. From the comparison, it is concluded that the source data of two-port acoustic source model are the traveling wave propagating outside along the duct under the acoustic boundary condition of full absorption at duct ends.

Integral barrier Lyapunov functions-based integrated guidance and control design for strap-down missile with field-of-view constraint

2021 ◽  
pp. 014233122098132
Author(s):  
Bin Zhao ◽  
Zhenxin Feng ◽  
Jianguo Guo
Keyword(s):  
Sliding Mode ◽  
State Equation ◽  
Field Of View ◽  
Feedback Form ◽  
Theoretical Derivation ◽  
Guidance And Control ◽  
Integrated Guidance And Control ◽  
Twisting Algorithm ◽  
And Control ◽  
Special Time

The problem of the integrated guidance and control (IGC) design for strap-down missile with the field-of-view (FOV) constraint is solved by using the integral barrier Lyapunov function (iBLF) and the sliding mode control theory. Firstly, the nonlinear and uncertainty state equation with non-strict feedback form for IGC design is derived by using the strap-down decoupling strategy. Secondly, a novel adaptive finite time disturbance observer is proposed to estimate the uncertainties based on an improved adaptive gain super twisting algorithm. Thirdly, the special time-varying sliding variable is designed and the iBLF is employed to handle the problem of FOV constraint. Theoretical derivation and simulation show that the IGC system is globally uniformly ultimately bounded and the FOV angle constraint is also guaranteed not only during the reaching phase but also during the sliding mode phase.

scholarly journals Acoustic Source Data for Medium Speed IC-Engines

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Antti Hynninen ◽  
Raimo Turunen ◽  
Mats Åbom ◽  
Hans Bodén
Keyword(s):  
High Frequency ◽  
Internal Combustion Engines ◽  
Low Frequency ◽  
Acoustic Source ◽  
Ic Engine ◽  
Source Characteristics ◽  
Medium Speed ◽  
Source Data ◽  
Exhaust Noise ◽  
Ic Engines

Knowledge of the acoustic source characteristics of internal combustion engines (IC-engines) is of great importance when designing the exhaust duct system and its components to withstand the resulting dynamic loads and to reduce the exhaust noise emission. The goal of the present study is to numerically and experimentally investigate the medium speed IC-engine acoustic source characteristics, not only in the plane wave range but also in the high frequency range. The low frequency acoustic source characteristics were predicted by simulating the acoustic multiload measurements by using a one-dimensional process simulation code. The low frequency in-duct exhaust noise of a medium speed IC-engine can be quite accurately predicted. The high frequency source data is estimated by averaging the measured acoustic pressures with different methods; using the simple cross-spectra averaging method seems promising in this instance.

scholarly journals An acoustic source model for asymmetric intraglottal flow with application to reduced-order models of the vocal folds

PLoS ONE ◽  
2019 ◽  
Vol 14 (7) ◽  
pp. e0219914
Author(s):  
Byron D. Erath ◽  
Sean D. Peterson ◽  
Kelley S. Weiland ◽  
Michael W. Plesniak ◽  
Matías Zañartu
Keyword(s):  
Vocal Folds ◽  
Source Model ◽  
Reduced Order Models ◽  
Acoustic Source ◽  
Reduced Order

A hydro‐acoustic source model in calculating noise field generated by breaking waves

2005 ◽  
Vol 118 (3) ◽  
pp. 2003-2003
Author(s):  
Xuemei Chen ◽  
Steven L. Means ◽  
William G. Szymczak ◽  
Joel C. W. Rogers
Keyword(s):  
Breaking Waves ◽  
Source Model ◽  
Acoustic Source ◽  
Noise Field

An Experimental Platform Based on Transfer Learning Paradigm for Mobile Robots

2013 ◽  
Vol 336-338 ◽  
pp. 960-963
Author(s):  
Hong Bo Lv ◽  
Jun Jie Tu ◽  
Qi Guo Sun ◽  
Fang Yuan Li ◽  
Jiao Wang ◽  
...  
Keyword(s):  
Mobile Robots ◽  
Transfer Learning ◽  
Source Model ◽  
Learning Paradigm ◽  
Knowledge Database ◽  
Experimental Platform ◽  
Source Data ◽  
Data Source ◽  
Model Training ◽  
Sd Card

The transfer learning paradigm promises to improve the adaptability of mobile robots which apply machine learning (ML) algorithms for perception and localization. An system framework based on transfer learning paradigm for mobile robots was proposed. The keys of the framework are 1) how to arrange the knowledge database, 2) how to select the source data, source model and priori knowledge, 3) the method to achieve the target model and 4) the method to gain new samples. An experimental platform was built up in order to gain data to verify the framework, whose underpan is the same as the Freescale Cup, MCUs core is ARM Cortex-M4, raw data is stored in a SD card and model is trained offline by a more powerful computer using ML algorithms. The MCU communicates with the powerful computer by Zigbee or WiFi. The experimental platform is cheap and feasible, which is validated by data collection and model training experiments.

scholarly journals Stability of detonation in a circular pipe with porous walls

2012 ◽  
Vol 370 (1960) ◽  
pp. 668-688 ◽  
Author(s):  
Carlos Chiquete ◽  
Anatoli Tumin
Keyword(s):  
Boundary Condition ◽  
Stability Problem ◽  
Temporal Stability ◽  
Porous Wall ◽  
Circular Pipe ◽  
Normal Velocity ◽  
Point Boundary ◽  
Acoustic Boundary Condition ◽  
Porous Walls ◽  
The Stability

A stability analysis is carried out taking into account slightly porous walls in an idealized detonation confined to a circular pipe. The analysis is carried out using the normal-mode approach and corrections are obtained to the underlying impenetrable wall case results to account for the effect of the slight porosity. The porous walls are modelled by an acoustic boundary condition for the perturbations linking the normal velocity and the pressure components and thus replacing the conventional no-penetration boundary condition at the wall. This new boundary condition necessarily complicates the derivation of the stability problem with respect to the impenetrable wall case. However, exploiting the expressly slight porosity, the modified temporal stability can be determined as a two-point boundary value problem similar to the case of a non-porous wall.

scholarly journals Charge Response of Jellium Surface through Ripplons

1982 ◽  
Vol 35 (2) ◽  
pp. 147
Author(s):  
J Mahanty
Keyword(s):  
Boundary Condition ◽  
Free Surface ◽  
Boundary Conditions ◽  
Surface Plasmons ◽  
Density Profile ◽  
External Source ◽  
Equilibrium Density ◽  
Response Properties ◽  
Surface Response ◽  
Dispersive Limit

The feasibility of explaining the charge response properties of a jellium surface through excitation of ripplon modes on the electron fluid is examined. It is demonstrated that for a sharp equilibrium density profile the response to the field of an external source through ripplons is different from that through surface plasmons, although in the non-dispersive limit they become identical despite the radical difference in the boundary conditions associated with the two types of excitation. It is suggested that because a free surface is more likely to satisfy the boundary condition for ripplons than for surface plasmons, the surface response properties would be determined more through the excitation of ripplons.

scholarly journals Robustness of Polynomial Stability of Damped Wave Equations

2022 ◽  
Author(s):  
Dmytro Baidiuk ◽  
Lassi Paunonen
Keyword(s):  
Boundary Condition ◽  
Wave Equations ◽  
Sufficient Conditions ◽  
Two Dimensional ◽  
Polynomial Stability ◽  
One Dimensional ◽  
Acoustic Boundary Condition ◽  
The Stability ◽  
Perturbed Equation ◽  
Dimensional Wave

AbstractIn this paper we present new results on the preservation of polynomial stability of damped wave equations under addition of perturbing terms. We in particular introduce sufficient conditions for the stability of perturbed two-dimensional wave equations on rectangular domains, a one-dimensional weakly damped Webster’s equation, and a wave equation with an acoustic boundary condition. In the case of Webster’s equation, we use our results to compute explicit numerical bounds that guarantee the polynomial stability of the perturbed equation.

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