scholarly journals Non-linear viscous damping and gravitational wave detectability of the f-mode instability in neutron stars

2012 ◽  
Vol 422 (4) ◽  
pp. 3327-3338 ◽  
Author(s):  
Andrea Passamonti ◽  
Kostas Glampedakis
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Viscous Damping ◽  
Mode Instability ◽  
Non Linear

scholarly journals THE R-MODE INSTABILITY IN ROTATING NEUTRON STARS

2001 ◽  
Vol 10 (04) ◽  
pp. 381-441 ◽  
Author(s):  
NILS ANDERSSON ◽  
KOSTAS D. KOKKOTAS
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Gravitational Waves ◽  
Binary Systems ◽  
Current Understanding ◽  
Mode Instability ◽  
Spin Evolution ◽  
Astrophysical Significance

In this review we summarize the current understanding of the gravitational-wave driven instability associated with the so-called r-modes in rotating neutron stars. We discuss the nature of the r-modes, the detailed mechanics of the instability and its potential astrophysical significance. In particular we discuss results regarding the spin-evolution of nascent neutron stars, the detectability of r-mode gravitational waves and mechanisms limiting the spin-rate of accreting neutron stars in binary systems.

scholarly journals Evolution of thef-mode instability in neutron stars and gravitational wave detectability

2013 ◽  
Vol 87 (8) ◽  
Author(s):  
A. Passamonti ◽  
E. Gaertig ◽  
K. D. Kokkotas ◽  
D. Doneva
Keyword(s):  
Neutron Stars ◽  
Gravitational Wave ◽  
Mode Instability

Problems on the Gravitational Wave and the Repulsive Gravitation

2016 ◽  
pp. 4422-4429
Author(s):  
C. Y. Lo
Keyword(s):  
Black Holes ◽  
Gravitational Wave ◽  
Einstein Equation ◽  
Wave Solution ◽  
Dynamic Solution ◽  
Pure Mathematics ◽  
Non Linear

It is exciting that the gravitational wave has been confirmed, according to the announcement of LIGO. This would be the time to fix the Einstein equation for the gravitational wave and the nonexistence of the dynamic solution. As a first step, theorists should improve their pure mathematics on non-linear mathematics and related physical considerations beyond Einstein. Then, it is time to rectify the Einstein equation that has no gravitational wave solution which Einstein has recognized, and no dynamic solution that Einstein failed to see. A problem is that physicists in LIGO did not know their shortcomings. Also, in view of the far distance of the sources, it is very questionable that the physicists can determine they are from black holes. Moreover, since the repulsive gravitation can also generate a gravitational wave, the problem of gravitational wave is actually far more complicated than we have known. A useful feature of the gravitational wave based on repulsive gravitation is that it can be easily generated on earth. Thus this can be a new tool for communication because it can penetrate any medium.

scholarly journals A Gravitational-Wave Perspective on Neutron-Star Seismology

Universe ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 97
Author(s):  
Nils Andersson
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Gravitational Wave ◽  
Fundamental Mode ◽  
Compact Binaries

We provide a bird’s-eye view of neutron-star seismology, which aims to probe the extreme physics associated with these objects, in the context of gravitational-wave astronomy. Focussing on the fundamental mode of oscillation, which is an efficient gravitational-wave emitter, we consider the seismology aspects of a number of astrophysically relevant scenarios, ranging from transients (like pulsar glitches and magnetar flares), to the dynamics of tides in inspiralling compact binaries and the eventual merged object and instabilities acting in isolated, rapidly rotating, neutron stars. The aim is not to provide a thorough review, but rather to introduce (some of) the key ideas and highlight issues that need further attention.

Energy Balancing Method to Identify Nonlinear Damping of Bolted-Joint Interface

2016 ◽  
Vol 693 ◽  
pp. 318-323 ◽  
Author(s):  
Xin Liao ◽  
Jian Run Zhang
Keyword(s):  
Dry Friction ◽  
Harmonic Excitation ◽  
Joint Interface ◽  
Damping Factor ◽  
Viscous Damping ◽  
Bolted Joint ◽  
Energy Balancing ◽  
Stick Slip ◽  
Non Linear ◽  
Linear Damping

The interface of bolted joint commonly focuses on the research of non-linear damping and stiffness, which affect structural response. In the article, the non-linear damping model of bolted-joint interface is built, consisting of viscous damping and Coulomb friction. Energy balancing method is developed to identify the dry-friction parameter and viscous damping factor. The corresponding estimation equations are acquired when the input is harmonic excitation. Then, the vibration experiments with different bolted preloads are conducted, from which amplitudes in various input levels are used to work out the interface parameters. Also, the fitting curves of dry-friction parameters are also obtained. Finally, the results illustrate that the most interface of bolted joint in lower excitation levels occurs stick-slip motion, and the feasibility of the identification approach is demonstrated.

scholarly journals Pendulum with aerodynamic and viscous damping

2020 ◽  
Vol 3 (2) ◽  
pp. 43-47
Author(s):  
Herlin Soraya
Keyword(s):  
Differential Equations ◽  
Stable State ◽  
The State ◽  
Linear Differential Equations ◽  
Viscous Damping ◽  
Viscous Damper ◽  
Aerodynamic Damping ◽  
Non Linear ◽  
Linear Differential ◽  
The Relationship

In this paper we discuss about how the relationship between non-linear differential equations on aerodynamic damping with linearly viscous damping equations. And it turns out after analyzing that the changes that occur pendulum that changes from the start of the maximum state to a stable state takes time so that changes that occur until the state is stable, this change can be reduced with the use of viscous damper

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