August 21, 2016

Stability Study of a Time-delayed Thermoacoustic System

  • Lei S.
  • Turan A.
  • Yang X.

In this paper, of primary concern is a time-delayed thermoacoustic system, viz. a horizontal Rijke tube. A continuation approach is employed to capture the nonlinear behavior inherent to the system. Unlike the conventional approach by the Galerkin method, a dynamic system is naturally built up by discretizing the acoustic momentum and energy equations incorporating appropriate boundary conditions using a finite difference method. In addition, the interaction of Rijke tube velocity with oscillatory heat release is modeled using a modified form of Kings law by Heckl. A comparison of the numerical results with experimental data and the calculations reported reveals that the current approach can yield very good predictions. Moreover, subcritical Hopf bifurcations and fold bifurcations are captured with the evolution of dimensionless heat release coefficient, generic damping coefficient and time delay. Linear stability boundary, nonlinear stability boundary, bistable region and limit cycles are thus determined to gain an understanding of the intrinsic nonlinear behaviors.

View Original Article

Recent Publications

August 28, 2024

Hybrid GMM-UBM and SVM based systems for text-independent speaker verification in noisy environment

  • Carvalho D.
  • Cavalcanti G.
  • Pinheiro H.
  • Sijbers J.
  • Tsang I.
  • Tsang I.

This paper proposes a hybrid Gaussian Mixture Model-Universal Background Model (GMM-UBM) based speaker verification system for mobile devices in variable noisy environments. We applied a Support Vector Machine (SVM) classier in two GMM-UBM based text-independent speaker verification systems to improve the performance. In the first system, both hypothesized speaker and ...

May 22, 2020

Energy Savings in LTE Macro Base Stations

  • Ambrosy A.
  • Blume O.
  • Ferling D.
  • Jueschke P.
  • Wilhelm M.
  • Yu X.

In wireless access networks the traffic load varies strongly along a day and efficient concepts to adapt the power consumption of LTE macro base stations to the required traffic load are currently widely under study. Significant daily energy savings up to 35% can be achieved for different deployment scenarios by ...

February 19, 2017

Enhancing Mobile Networks with Software Defined Networking and Cloud Computing

  • Cao Z.
  • Kodialam M.
  • Lakshman T.
  • Panwar S.

In the past decade, mobile devices and applications have experienced an explosive growth, and users are expecting higher data rates and better quality services every year. In this paper, we propose several ideas to increase wireless network functionality and capacity using software-defined networking and cloud computing. Connections in mobile networks ...