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Sunetra Sarkar

Bio: Sunetra Sarkar is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Airfoil & Polynomial chaos. The author has an hindex of 16, co-authored 95 publications receiving 819 citations. Previous affiliations of Sunetra Sarkar include Delft University of Technology & Indian Institute of Science.


Papers
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Journal ArticleDOI
TL;DR: In this article, a nonlinear dynamic problem of stall induced flutter oscillation subject to physical uncertainties is analyzed using arbitrary polynomial chaos, in which appropriate expansion polynomials are constructed based on the statistical moments of the uncertain input.

140 citations

Journal ArticleDOI
TL;DR: In this paper, a parametric study on the aeroelastic instability and the nonlinear dynamical behavior of a two-dimensional symmetric rotor blade in the dynamic stall regime is investigated.

61 citations

Journal ArticleDOI
TL;DR: In this article, a probabilistic collocation for limit cycle oscillations (PCLCO) is proposed, which is a non-intrusive approach to compute the polynomial chaos description of uncertainty numerically.

55 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the complex vortex interactions in two-dimensional flow-field behind a symmetric NACA0012 airfoil undergoing a prescribed periodic pitching-plunging motion in low Reynolds number regime.
Abstract: The present study investigates the complex vortex interactions in two-dimensional flow-field behind a symmetric NACA0012 airfoil undergoing a prescribed periodic pitching-plunging motion in low Reynolds number regime. The flow-field transitions from periodic to chaotic through a quasi-periodic route as the plunge amplitude is gradually increased. This study unravels the role of the complex interactions that take place among the main vortex structures in making the unsteady flow-field transition from periodicity to chaos. The leading-edge separation plays a key role in providing the very first trigger for aperiodicity. Subsequent mechanisms like shredding, merging, splitting, and collision of vortices in the near-field that propagate and sustain the disturbance have also been followed and presented. These fundamental mechanisms are seen to give rise to spontaneous and irregular formation of new vortex couples at arbitrary locations, which are the primary agencies for sustaining chaos in the flow-field. The...

47 citations

Journal ArticleDOI
TL;DR: In this article, the aeroelastic response of a NACA 0012 airfoil in the flow regimes prior to flutter is investigated in a wind tunnel, where the authors observe intermittent bursts of periodic oscillations in the pitch and plunge response, that appear in an irregular manner from a background of relatively lower amplitude aperiodic fluctuations.

44 citations


Cited by
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Journal ArticleDOI
TL;DR: A non intrusive method that builds a sparse PC expansion, which may be obtained at a reduced computational cost compared to the classical ''full'' PC approximation.

1,112 citations

01 Jan 2007
TL;DR: Two algorithms for generating the Gaussian quadrature rule defined by the weight function when: a) the three term recurrence relation is known for the orthogonal polynomials generated by $\omega$(t), and b) the moments of the weightfunction are known or can be calculated.
Abstract: Most numerical integration techniques consist of approximating the integrand by a polynomial in a region or regions and then integrating the polynomial exactly. Often a complicated integrand can be factored into a non-negative ''weight'' function and another function better approximated by a polynomial, thus $\int_{a}^{b} g(t)dt = \int_{a}^{b} \omega (t)f(t)dt \approx \sum_{i=1}^{N} w_i f(t_i)$. Hopefully, the quadrature rule ${\{w_j, t_j\}}_{j=1}^{N}$ corresponding to the weight function $\omega$(t) is available in tabulated form, but more likely it is not. We present here two algorithms for generating the Gaussian quadrature rule defined by the weight function when: a) the three term recurrence relation is known for the orthogonal polynomials generated by $\omega$(t), and b) the moments of the weight function are known or can be calculated.

1,007 citations

01 Jan 2006
TL;DR: The mysterious rattleback and its fluid counterpart:Developments in shear instabilities(Patrick Huerre,Falling clouds+Elisabeth Guazzelli)LEcotectural fluid mechanics%Herbert Huppert )
Abstract: 流体力学杂志“Journal of Fluid Mechanics”由剑桥大学教授George Batchelor在1956年5月创办,在国际流体力学界享有很高的学术声望,被公认为是流体力学最著名的学术刊物之一,2005年的影响因子为2.061,雄居同类期刊之首.在它创刊50周年之际,2006年5月JFM出版了第554卷的纪念特刊,其中刊登了现任主编(美国西北大学S.H.Davis教授和英国剑桥大学T.J.Pedley教授)合写的述评:“Editorial:JFM at50”,以JFM为背景,从独特的视角对近50年来流体力学的发展进行了简明的回顾和展望,并归纳了一系列非常有启发性的有趣统计数字.2006年7月21日在剑桥大学应用数学和理论物理研究所(DAMTP)举行了创刊50周年的庆祝会.下午2点,JFM的新老编辑和来宾会聚一堂,Pedley教授致开幕词,其后是5个精彩的报告:The mysterious rattleback and its fluid counterpart(Keith Moffatt),Developments in shear instabilities(Patrick Huerre),Falling clouds(Elisabeth Guazzelli),Ecotectural fluid mechanics(Paul Linden),The success of JFM(Herbert Huppert),最后由Davis教授致闭幕词.

767 citations

01 Jul 1994
TL;DR: In this article, the effects of large computational time steps on the computed turbulence were investigated using a fully implicit method in turbulent channel flow computations and the largest computational time step in wall units which led to accurate prediction of turbulence statistics was determined.
Abstract: Effects of large computational time steps on the computed turbulence were investigated using a fully implicit method. In turbulent channel flow computations the largest computational time step in wall units which led to accurate prediction of turbulence statistics was determined. Turbulence fluctuations could not be sustained if the computational time step was near or larger than the Kolmogorov time scale.

470 citations

Journal ArticleDOI
TL;DR: The key idea is to align the complexity level and order of analysis with the reliability and detail level of statistical information on the input parameters to avoid the necessity to assign parametric probability distributions that are not sufficiently supported by limited available data.

350 citations