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Announcements related to HPCL

Graduating students' farewell at HPCL in 2015. Photo

Book review of Theoretical and Computational Aerodynamics (John Wiley, UK) appeared in Aeronautical Journal of Royal Aeronautical Society. Writing this book was possible with help from all at HPCL.

Transition to turbulence-- the physical mechanism explained in:
Precursor of Transition to Turbulence: spatiotemporal wave front
by: Swagata Bhaumik and Tapan K Sengupta; In: Physical Review E.
PREVIEW LINK: http://spectral.iitk.ac.in/hpcl/LH13761E_25April2014.pdf
Journal link: http://journals.aps.org/pre/accepted/b307fY87Ub91fc3bd7776bb1d6fd45e9cb1...
Recent developments announced in the IUTAM SYMPOSIUM URL: http://spectral.iitk.ac.in/hpcl/IUTAM2014


Third International Conference on Meta Computing 2012, held in Bhubaneswar. Conference Co-Chair: Prof. Tapan K Sengupta
Best papers: Drs. V. Mudkavi/ K. Venkatesh (NAL Bangalore) and Pramod Bagade/ B. Satish (IIT Kanpur)


DNS of Transition and Turbulence in Physical Review Letters - see link (1) below.
Also the paper: "Direct numerical simulation of two-dimensional wall-bounded turbulent flows
from receptivity stage" February 2012, Physical Review E (Vol.85, No.2):
URL: http://link.aps.org/doi/10.1103/PhysRevE.85.026308
Related links :
(1) http://prl.aps.org/abstract/PRL/v107/i15/e154501
(2) http://prl.aps.org/abstract/PRL/v96/i22/e224504
(3) http://www.sciencedirect.com/science/article/pii/S0021999107002537

The IIT Kanpur, HPCL group has provided definitive answers to CAUSALITY of turbulence
in wall bounded boundary layers. Through the work on Bromwich contour integral method
(developed in IITK since 1990) spatio-temporal wave-front (STWF) have been shown as the main
precursor to transition and turbulence (PRL, 2006, 2011, PRE 2014 and the CRC text book, see the side-bar).
High accuracy computing of Navier-Stokes equation also attest to formation of STWF leading to fully-developed
turbulence via deterministic excitation of laminar flow in RECEPTIVITY framework.

News

    "Summer visitors/ interns at HPCL: i) Prof. Manoj K Rajpoot is here to work on GSA of Rossby wave equation, error analysis and DNS. ii) Kartika (BHU) on Robins-Magnus effect for a new viscous instability at super-critical rotation rates, taking help from Ijlal and Atchyut. iii) Akash (IIT Kanpur) with Atchyut to work on ROM for flow past airfoils. The ROM for circular cylinder has been performed by three different routes and (iv) Prayash and Aditi are working along with Prof. Rajpoot on compact schemes on non-uniform grid. They are using GSA as the working tool. The developments to be used for LDC at post-critical Reynolds numbers."

The summer is over and visitors are back! Dr. Rajpoot's company was enjoyed by one and all. We did not have time to talk on Rossby waves. He was busy with compact schemes in non-uniform grids with Prayash and Aditi. Our work on ROM has yielded some good insight. Hence Atchyut and Akash will continue their work. Pramod is working feverishly on his thesis. It is great to see him focus on his results. Vishal is back from his internship from USA. He is looking at LEC now.
On the job front: Akhil has joined Rolls Royce; Ijlal is placed with Airbus. Neelesh is teaching in Pune/ Mumbai. Prasoon has joined Georgia Tech. Aditi is heading to Cambridge. Good news is that Shruti has come back to HPCL. She and Roshan keeps doing things with lots of vigour.

Good news from Dr. AK Rao (we call him Kamesh): He will join IIT Madras in Dept. of Mechanical Engineering very soon.
You probably are all aware that Prof. Manoj T. Nair is the faculty member at IIST in Thiruvananthapuram, Dr. Sudipta De is at CMERI Durgapur and Prof. Venkatasubbaiah is in IIT Hyderabad. Other senior members of HPCL: Sarthok Sircar is a faculty at Univ. of Adellaide; Anurag Dipankar is with MPI at Hamburg. Help me fill up this space with other co-ordinates!

TKS attended a conference on Thermodynamics in Nancy, France during May. He visited ISM Dhanbad to inaugurate workshop on HPC. This semester he teaches AE603 and AE605. Focus of AE605 is more analysis of Fourier Spectral Methods with and without hyperviscosity. Promise to communicate the results soon. TKS will attend Turbulence and Interaction (TI-2015) in Corsica, France to give an invited talk mainly on the central role of spatio-temporal wave-front (2-6 Nov. 2015). There is universality in the unit process of STWF, something similar to our work on universality of POD modes (2009) would be discussed!

    Work published on Reduced Order Modeling by POD: Physical Review E, vol. 91(4), 043303 (2015) DOI: 10.1103/PhysRevE.91.043303

    GSA of Bi-Directional Wave Equation: J. Computational Physics (2015)
This began as a term paper for AE605 (Advanced Scientific Computing) and the authors are a select group of students who have performed the work successfully.

    IUTAM symposium on Advances in Computation, Modeling and Control of Transitional and Turbulent Flows was held in Goa, India during 15-18 December, 2014. The materials for the proceedings are with the publisher. We hope to see it in print soon. Visit the web-site: http://spectral.iitk.ac.in/hpcl/IUTAM2014

    Paper titled Precursor of transition to turbulence: Spatio-temporal wave front by Dr. Swagata Bhaumik and Tapan Sengupta has appeared in Phys. Rev. E. Click here for paper

    Article Usage for: "Direct Numerical Simulation of 2D Transonic Flows around Airfoils," Sengupta T.K., Bhole A., Sreejith N.A., Click here

    HPCL news: " KdV equation and computation of Solitons: Nonlinear error dynamics," Ashwin Vishnu M, Kumar Saurabh, M Sriramkrishnan, PM Bagade, MK Parvathi and Sengupta T.K., This is an outcome of a term paper by the listed students in AE605.

    "Diffusion in inhomogeneous flows: Unique equilibrium state in an internal flow," Tapan K. Sengupta, Himanshu Singh, Swagata Bhaumik, Rajarshi Roy Chowdhury. This is one of our major works, where we show how small scales are created in fluid flow, irrespective of dimensionality. As this is for inhomogeneous flow sans assumptions, it provides an important result.

    The book : "Theoretical and Computational Aerodynamics" has been published by Wiley, UK. This contains chapters on (i) computational aerodynamics, (ii) NLF and transitional flow related to aerodynamics, (iii) transonic aerodynamics and (iv) low Reynolds number unsteady aerodynamics. Soon a companion volume to appear with problems and lots of animations explaining certain aspects of Aerodynamics.

    The book: "High Accuracy Computing Methods: Fluid Flows and Wave Phenomena" is published by Cambridge University Press (2013) with an Indian edition available. Foreword written by Prof. Michel Deville. See:
http://www.cambridge.org/9781107023635

    Swagata Bhaumik defended his Ph.D. thesis on 2D and 3D flow receptivity and transition. He is at OSU with Prof. D. V. Gaitonde. His work on transition and turbulence is culmination of contributions by HPCL over the past two decades, starting with the work on Bromwich contour integral methods.

    Our work on rectangular lid driven cavity is published in Computers and Fluids, highlighting the enstrophy cascade mechanism for inhomogeneous flow and is a significant improvement over existing ideas on energy cascade based on homogeneous isotropic turbulence. This, unlike Kolmogorov's theory, is equally true for 2D and 3D flows for the cascade of scales.

    A 40 parts lecture series on Foundations of Scientific Computing taught to IIT Kanpur undergraduate students (2009) as a science elective is available in You Tube and in:
http://nptel.iitm.ac.in/courses/101104013/1

    TKS visited in 2012: (i) Ecole Polytechnique, Montreal (June-July, 2012); (ii) Center for Advanced Studies in Theoretical Sciences (CASTS) and Taida Institute of Mathematical Sciences (TIMS) at National Taiwan Univ., Taipei, Taiwan for Progress in Mathematical and Computational Studies on Science and Engineering Problems conference, 5 - 7 November, 2012. Photo

    Dr. Yogesh Bhumkar, after his Ph.D. spent a short stint at NTU, Taipei. He is currently a faculty member in IIT Bhubhaneswar and doing great!

    The book: "Instabilities of Flows and Transition to Turbulence" published by CRC Press, Taylor & Francis Group, USA is available. Details of the book are in:
http://www.crcpress.com/product/isbn/9781439879443

    Prof. T. K. Sengupta has helped Tata McGraw-Hill for the Indian edition of Fundamentals of Aerodynamics by Prof. J. D. Anderson, augmented with SI Metrication and a chapter on Aerodynamic Research Activities in India written by him.

    Prof. Michel Deville's visit to HPCL in 2010: Prof. Michel Deville ( Ecole Polytechnique Federale de Lausanne, Switzerland) visited HPCL and delivered lectures on Spectral Element Method . Photo

    Recent trends in HPC at HPCL, IIT Kanpur, Sep 2009: Account of work done in HPCL, IIT Kanpur, on methods for DNS/ LES was displayed in the Workshop on "High Performance Computing in India" in conjunction with "Supercomputing 2009" (SC09), Nov. 14-20, 2009 (USA). Because of refusal in granting visa by USA embassy in Delhi, no one could be present personally.

    Issues related to DNS / LES were the central themes of the plenary talk given at the Fifth M.I.T. conference at Boston, June 2009

1. Three-time level methods like second order Adam-Bashforth schemes are incorrectly used for "DNS". Following papers show that numerical/ spurious mode removes large fraction of initial condition at higher frequencies. Details in HIGH ACCURACY COMPUTING METHOD (CUP, 2013) and the following papers:

a) A Comparative Study of Time Advancement Methods for Solving Navier-Stokes Equations

Dowload comparative study.. paper from springerlink

b) High Accuracy Schemes for DNS and Acoustics

Download the DNS and acoustics paper from springerlink

2. The von Neumann analysis for PDEs has been corrected, with the help of 1D convection equation. See the CUP book and the following from J. Computational Physics:

a) Error Dynamics: Beyond von Neumann Analysis -- T.K. Sengupta, A. Dipankar and P. Sagaut, 226, 1211-1218 (2007)
Dowload Error dynamics: Beyond von Neumann analysis paper from Science Direct