A5090677791- Fluid Dynamics and Turbulent Flows
- Wind and Air Flow Studies
- Atmospheric aerosols and clouds
- Plant Water Relations and Carbon Dynamics
- Meteorological Phenomena and Simulations
- Particle Dynamics in Fluid Flows
- Aerodynamics and Acoustics in Jet Flows
- Heat Transfer Mechanisms
- Aeolian processes and effects
- Atmospheric chemistry and aerosols
- Climate variability and models
- Tropical and Extratropical Cyclones Research
- Air Quality and Health Impacts
- Hydrology and Sediment Transport Processes
- Precipitation Measurement and Analysis
- Mechanics and Biomechanics Studies
- Nuclear Engineering Thermal-Hydraulics
- Combustion and flame dynamics
- Electric Power System Optimization
- Dynamics and Control of Mechanical Systems
- Robotic Mechanisms and Dynamics
- Atmospheric Ozone and Climate
- Fluid Dynamics and Vibration Analysis
- Plasma and Flow Control in Aerodynamics
- Navier-Stokes equation solutions
Indian Institute of Tropical Meteorology
2013-2025
Ministry of Earth Sciences
2020-2025
Rayat Shikshan Sanstha
2013
Indian Institute of Science Bangalore
2008-2010
The objectives of the Winter Fog Experiment (WIFEX) over Indo-Gangetic Plains India are to develop better now-casting and forecasting winter fog on various time-and spatial scales.Maximum occurrence northwest is about 48 days (visibility <1000 m) per year, it occurs mostly during December-February time-period.The physical chemical characteristics fog, meteorological factors responsible for its genesis, sustenance, intensity dissipation poorly understood.Improved understanding above aspects...
We present a novel generalized scaling framework and predictive model for wall friction in turbulent flows. The is derived from the dynamical equations, total mean-flow kinetic energy velocity profile shape factor are used as surrogates boundary condition effects. Veracity of approach assessed using data literature spanning unprecedented ranges flow types, Reynolds numbers, accelerations, history Unlike previous models that solely apply to standard flows, reconciles nonstandard flows with...
Statistical and fractal properties of the scalar interface in a plane turbulent wall jet air are investigated experimentally. Seeding is introduced for only flow. These seed particles do not diffuse or evaporate quickly, contrast to smoke that commonly used flows. Three cameras placed one above other operated single-frame mode image instantaneous between seeded unseeded ambient fluid with sub-Kolmogorov spatial resolution an unprecedented dynamic range (large-to-small scale ratio) 2450. The...
Abstract The demand for effective methods to augment precipitation over arid regions of India has been increasing the past several decades as changing climate brings warmer average temperatures. In fourth phase Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX IV), a scientific investigation was conducted rain-shadow region Western Ghats mountains in India. primary objective investigate efficacy hygroscopic seeding convective clouds develop cloud protocol. CAIPEEX...
Experiments were done on sink flow turbulent boundary layers over a wide range of streamwise pressure gradients in order to investigate the effects mean velocity profiles. Measurements revealed existence non-universal logarithmic laws, both inner and defect coordinates, even when descriptions departed strongly from universal law (with values Kármán constant intercept). Systematic dependences slope intercepts for outer laws strength gradient observed. A theory based method matched asymptotic...
Aspects of large-scale organized structures in sink flow turbulent and reverse-transitional boundary layers are studied experimentally using hot-wire anemometry. Each the present is a state ‘perfect equilibrium’ or ‘exact self-preservation’ sense Townsend ( The Structure Turbulent Shear Flow , 1st 2nd edns, 1956, 1976, Cambridge University Press) Rotta Progr. Aeronaut. Sci ., vol. 2, 1962, pp. 1–220) conforms to notion ‘pure wall-flow’ (Coles, J. Aerosp. 24, 1957, 495–506), at least for...
Plane turbulent wall jets are traditionally considered to be composed of a boundary layer (TBL) topped by half-free jet. However, certain peculiar features, such as counter-gradient momentum flux occurring below velocity maximum in experiments and numerical simulations, suggest different structure turbulence therein. Here, we hypothesize that has two distinct structural modes, mode scaling on variables free-jet jet variables. To investigate this hypothesis, experimental data from our...
Studies in the literature on plane turbulent wall jets flat surfaces, have invariably considered either nozzle initial conditions or asymptotic far downstream, as scaling parameters for streamwise variations of length and velocity scales. These choices, however, do not square with notion self similarity which is essentially a "local" concept. We first demonstrate that scales show remarkable local i.e. there appear to be no imposed Next, it shown mean profile data suggest existence two...
© 2022 American Meteorological Society. For information regarding reuse of this content and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses). Corresponding author: Lulin Xue, xuel@ucar.edu
This study reports on new particle formation (NPF) and characteristic features observed from a rural site falling in the rainshadow of Western Ghats peninsular India. A total 35 NPF events during August 2018 - January 2019 are classified analyzed here. The apparent rates ranged 0.2 to 10.0 cm–3 s–1, while growth nucleation mode particles 1.2 13.8 nm h–1. frequency occurrence was least (core monsoon) highest post-monsoon. local winds were calm southeasterly easterly (from urban centre)...
Abstract. Continuous aerosol and cloud condensation nuclei (CCN) measurements carried out at the ground observational facility situated in rain-shadow region of Indian subcontinent are illustrated. These observations were part Cloud Aerosol Interaction Precipitation Enhancement Experiment (CAIPEEX) during summer monsoon season (June to September) 2018. Observations classified as dry–continental (monsoon break) wet–marine active) according air mass history. CCN concentrations measured for a...
A new asymptotic −1/2 power-law scaling is derived from the momentum integral equation for drag in flat-plate turbulent boundary layers. In limit of infinite Reynolds number, appropriate velocity scale found to be M/ν, where M layer kinematic rate and ν fluid viscosity. Data covering a wide range numbers remarkably collapse universal curve variables. Two models, discrete continuous, are proposed this curve, robust estimation method, based on these also presented.
The El Nino and Southern Oscillation (ENSO) 'diversity' has been considered as a major factor limiting its predictability, critical need for disaster mitigation associated with the trademark climatic swings of ENSO. Improving climate models ENSO forecasts relies on deeper understanding diversity but currently at nascent stage. Here, we show that thought previously 'complex,' arises largely varied contributions from three leading modes to given event. 'slow manifold' can be fully described by...
Friction factor models for turbulent flow in smooth pipes express friction λ as a function of the bulk Reynolds number ReD and may be broadly grouped into two categories: power-law log-law models. While former stem from spectral scaling arguments applied to eddy momentum transfer close wall, latter are derived mean velocity log law known consistent with attached model wall turbulence structure. Interestingly, none these individually describes entire range numbers (Re) accessed date, without...
High Reynolds number is thought to be a fundamental condition essential for the occurrence of log scaling in turbulent boundary layers. However, while variation mean velocity seen occur at moderate numbers traditional layer literature, variations higher-order moments are evident only much higher numbers, as reported recent experiments. This observation suggests that, underlying layers, there exists more (apart from largeness number) – requirement self-similar evolution mean-flow quantity...
Abstract Scaling of the streamwise velocity spectrum ${\phi }_{11} ({k}_{1} )$ in so-called sink-flow turbulent boundary layer is investigated this work. The present experiments show strong evidence for ${ k}_{1}^{- 1} $ scaling i.e. )= {A}_{1} { U}_{\tau }^{2} , where ${k}_{1} wavenumber and ${U}_{\tau } friction velocity. Interestingly, observed much farther from wall at lower flow Reynolds number (both differing by almost an order magnitude) than what expectations on a...
A dynamically consistent scaling of mean skin friction in zero-pressure-gradient turbulent boundary layers and fully developed pipe channel flows, is derived. Theoretical arguments are based on transfer kinetic energy from flow to large eddies turbulence. single new velocity scale $M/\nu$ shown be relevant for all flows; $M$ the planar kinematic momentum rate shear $\nu$ fluid viscosity. An asymptotic $-1/2$ power law (in – scaling) universally applicable. It observed that semi-empirical...
Abstract. Cloud seeding experiments for modifying clouds and precipitation have been underway nearly a century; yet practically all the attempts to link enhancement or suppression presence of materials within remain elusive. In 2019, Cloud–Aerosol Interaction Precipitation Enhancement Experiment (CAIPEEX) investigated residuals cloud hydrometeors in seeded non-seeded with an airborne mini aerosol mass spectrometer (mAMS). The mAMS was utilized conjunction counterflow virtual impactor (CVI)...