Experimental Investigation of Finite-Sized Inertial Particles Dynamics in Wind Tunnel Grid Generated Turbulence

Abstract : In the current research work, the effects of particle's finite size and density on their Lagrangian dynamics in turbulent flow have been explored. The flow type is grid generated wind tunnel turbulence. Gas inflated soap bubbles are used as particles whose size and density can be adjusted as per requirement within an attainable range. The particles injected into the flow are tracked in a Lagrangian manner employing the state-of-the-art Ultrasonic Doppler Velocimetry. A range of particle sizes and densities were studied by systematically varying them, while keeping flow configuration the same. For each set of particle size and density their Lagrangian velocity and acceleration statistics were calculated after recording thousands of velocity signals. The Lagrangian velocity PDFs were found to be Gaussian and: independent of particle size and density; and identical to the Eulerian velocity PDFs of the carrier flow. Regarding particles Lagrangian acceleration, no effect of particle size and density was observed on the normalized acceleration PDFs. These effects were only observed upon particles acceleration variance which for neutrally buoyant particles decreases monotonically with increasing particle size. However, for heavier particles the finite size effects on particles acceleration variance can be trivially extrapolated neither from heavy point particle limit nor from neutrally buoyant case. The dynamics of all the data sets studied were found to be intermittent. The particles response to turbulent forcing, obtained from acceleration autocorrelations was found not to vary much as it remains of the order of kolmogorov's time scale for all the data sets as compared with particles response time.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00391843
Contributor : Muhammad Nauman Qureshi <>
Submitted on : Friday, June 5, 2009 - 9:12:00 AM
Last modification on : Thursday, January 3, 2019 - 4:30:08 PM
Long-term archiving on : Thursday, June 10, 2010 - 10:13:01 PM

Identifiers

  • HAL Id : tel-00391843, version 1

Collections

UJF | LEGI | UGA

Citation

Muhammad Nauman Qureshi. Experimental Investigation of Finite-Sized Inertial Particles Dynamics in Wind Tunnel Grid Generated Turbulence. Mechanics [physics.med-ph]. Université Joseph-Fourier - Grenoble I, 2009. English. ⟨tel-00391843⟩

Share

Metrics

Record views

485

Files downloads

1015