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Anupam Sharma

Bio: Anupam Sharma is an academic researcher from Iowa State University. The author has contributed to research in topics: Aerodynamics & Airfoil. The author has an hindex of 15, co-authored 62 publications receiving 654 citations. Previous affiliations of Anupam Sharma include General Electric & Indian Institute of Technology Bombay.


Papers
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Journal ArticleDOI
TL;DR: In this paper, a landing gear in a uniform flow is computed using the Ffowcs Williams-Hawkings (FW-H) equation using a finite volume low-order flow solver on an unstructured grid.
Abstract: Aerodynamic noise from a landing gear in a uniform flow is computed using the Ffowcs Williams-Hawkings (FW-H) equation. The time accurate flow data on the integration surface is obtained using a finite volume low-order flow solver on an unstructured grid. The Ffowcs Williams-Hawkings equation is solved using surface integrals over the landing gear surface and over a permeable surface away from the landing gear. Two geometric configurations are tested in order to assess the impact of two lateral struts on the sound level and directivity in the far-field. Predictions from the Ffowcs Williams-Hawkings code are compared with direct calculations by the flow solver at several observer locations inside the computational domain. The permeable Ffowcs Williams-Hawkings surface predictions match those of the flow solver in the near-field. Far-field noise calculations coincide for both integration surfaces. The increase in drag observed between the two landing gear configurations is reflected in the sound pressure le...

73 citations

Journal ArticleDOI
16 Jun 2014
TL;DR: In this article, a dual-rotor wind turbine (DRWT) concept is proposed that aims at mitigating the aerodynamic inefficiencies in the blade root region (near the hub) due to several non-aerodynamic constraints.
Abstract: Horizontal axis wind turbines suer from aerodynamic ineciencies in the blade root region (near the hub) due to several non-aerodynamic constraints. Aerodynamic interactions between turbines in a wind farm also lead to signicant loss of wind farm eciency. A new dual-rotor wind turbine (DRWT) concept is proposed that aims at mitigating these two losses. A DRWT is designed that uses an existing turbine rotor for the main rotor, while the secondary rotor is designed using a high lift-to-drag ratio airfoil. Reynolds Averaged Navier- Stokes computational uid dynamics simulations are used to optimize the design. Large eddy simulations conrm the increase energy capture potential of the DRWT. Wake comparisons however do not show enhanced entrainment of axial momentum.

67 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a numerical analysis of an airfoil geometry inspired by the down coat of the night owl and compare the performance of the bio-inspired and baseline NACA 0012 airfoils.

53 citations

Journal ArticleDOI
01 May 2005
TL;DR: In this article, the authors used computational fluid dynamics (CFD) simulations of ship airwakes to simulate landing helicopter assault (LHA) and landing platform (LSTM).
Abstract: Computational fluid dynamics (CFD) simulations of ship airwakes are discussed in this article. CFD is used to simulate the airwakes of landing helicopter assault (LHA) and landing platform ...

45 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of airfoil thickness on the onset of dynamic stall was investigated using large eddy simulations at chord-based Reynolds number of 200,000, where the Navier-Stokes solver was used with a sixth-order compact finite difference scheme for spatial discretization, secondorder implicit time integration and discriminating filters to remove unresolved wavenumbers.
Abstract: Effect of airfoil thickness on onset of dynamic stall is investigated using large eddy simulations at chord-based Reynolds number of 200 000. Four symmetric NACA airfoils of thickness-to-chord ratios of 9 %, 12 %, 15 % and 18 % are studied. The three-dimensional Navier–Stokes solver, FDL3DI is used with a sixth-order compact finite difference scheme for spatial discretization, second-order implicit time integration and discriminating filters to remove unresolved wavenumbers. A constant-rate pitch-up manoeuver is studied with the pitching axis located at the airfoil quarter chord. Simulations are performed in two steps. In the first step, the airfoil is kept static at a prescribed angle of attack (). In the second step, a ramp function is used to smoothly increase the pitch rate from zero to the selected value and then the pitch rate is held constant until the angle of attack goes past the lift-stall point. The solver is verified against experiments for flow over a static NACA 0012 airfoil. Static simulation results of all airfoil geometries are also compared against XFOIL predictions with a generally favourable agreement. FDL3DI predicts two-stage transition for thin airfoils (9 % and 12 %), which is not observed in the XFOIL results. The dynamic simulations show that the onset of dynamic stall is marked by the bursting of the laminar separation bubble (LSB) in all the cases. However, for the thickest airfoil tested, the reverse flow region spreads over most of the airfoil and reaches the LSB location immediately before the LSB bursts and dynamic stall begins, suggesting that the stall could be triggered by the separated turbulent boundary layer. The results suggest that the boundary between different classifications of dynamic stall, particularly leading edge stall versus trailing edge stall, is blurred. The dynamic-stall onset mechanism changes gradually from one to the other with a gradual change in some parameters, in this case, airfoil thickness.

40 citations


Cited by
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TL;DR: This book is coming as the best seller book today and when you are really a good reader or you're fans of the author, it does will be funny if you don't have this book.
Abstract: Follow up what we will offer in this article about philosophical transactions of the royal society of london series b biological sciences no 600 vol 233 studies of the post glacial history of british vegetation x correlation between climate forest composition prehistoric agriculture and peat st. You know really that this book is coming as the best seller book today. So, when you are really a good reader or you're fans of the author, it does will be funny if you don't have this book. It means that you have to get this book. For you who are starting to learn about something new and feel curious about this book, it's easy then. Just get this book and feel how this book will give you more exciting lessons.

607 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: In this article, the Kirchhoff formulation for moving surfaces is compared with the Ffowcs Williams Hawkings (FW-H) equation for the prediction of high-speed impulsive noise, in an effort to eliminate the need to compute the quadrupole contribution.

420 citations

01 Jan 2016
TL;DR: In this article, the atmospheric boundary layer flows their structure and measurement, but end up in malicious downloads, rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some malicious virus inside their laptop.
Abstract: Thank you very much for reading atmospheric boundary layer flows their structure and measurement. As you may know, people have search numerous times for their chosen books like this atmospheric boundary layer flows their structure and measurement, but end up in malicious downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some malicious virus inside their laptop.

220 citations