Round Turbulent Thermals, Puffs, Starting Plumes and Starting Jets in Uniform Crossflow  

Oleh:

Diez, F. J. ; Bernal, L. P. ; Faeth, G. M.

Jenis: Article from Bulletin/Magazine
Dalam koleksi: Journal of Heat Transfer vol. 125 no. 6 (Dec. 2003), page 1046-1057.
Topik: thermal conductivity; round turbulent; thermals; puffs; starting plumes; jets; uniform crossflow

Ketersediaan

Perpustakaan Pusat (Semanggi) Nomor Panggil: JJ90.7 Non-tandon: 1 (dapat dipinjam: 0) Tandon: tidak ada

Lihat Detail Induk

Isi artikel

The self - preserving properties of round turbulent thermals, puffs, starting plumes and starting jets, in unstratified and uniform crossflow, were investigated experimentally. The experiments involved dye - containing fresh water (for nonbuoyant flows) and salt water (for buoyant flows) sources injected vertically downward into crossflowing fresh water within a water channel. Time - resolved video images of the flows were obtained using CCD cameras. Experimental conditions were as follows: source exit diameters of 3.2 and 6.4 mm, source Reynolds numbers of 2,500 – 16,000, source / ambient velocity ratios of 4 – 35, source / ambient density ratios (for buoyant flows) of 1.073 and 1.150, volumes of injected source fluid (for thermals and puffs) comprising 16 – 318 source diameters, streamwise (vertical) penetration distances of 0 – 200 source diameters and 0 – 13 Morton length scales (for buoyant flows) and crosstream (horizontal) penetration distances of 0 – 620 source diameters. Near - source behavior varied significantly with source properties and distance from the source but the flows generally became turbulent for streamwise distances within 5 source diameters from the source and became self - preserving for streamwise distances from the source greater than 40– 50 source diameters. Crosstream motion satisfied the no - slip convection approximation. Streamwise motion for self - preserving conditions satisfied the behaviour of corresponding self - preserving flows in still fluids : round thermals and puffs in still fluids for round thermals and puffs in crossflow and two - dimensional line thermals and puffs in still fluids for round starting plumes and jets in crossflow. The no-slip convection approximation for crossflow motion combined with self - preserving approximations for streamwise motion were also effective for predicting flow trajectories at self - preserving conditions for steady round turbulent plumes and jets in crossflow.

Opini Anda

Klik untuk menuliskan opini Anda tentang koleksi ini!

Kembali