Turbulent Statistics of a Hot, Overexpanded Rectangular Jet

2022 ◽  
pp. 1-16
Author(s):  
Surya Chakrabarti ◽  
Datta V. Gaitonde ◽  
Sasidharan Nair Unnikrishnan ◽  
Cory Stack ◽  
Florian Baier ◽  
...  
Keyword(s):  
Rectangular Jet ◽  
Turbulent Statistics

3-D LDA study of a rectangular jet

1988 ◽  
Author(s):  
GERALD MORRISON ◽  
GARY TATTERSON
Keyword(s):  
Rectangular Jet

scholarly journals Investigation of Separation Phenomena in a Radial Pump at Reduced Flow Rate by Large-Eddy Simulation

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Antonio Posa ◽  
Antonio Lippolis ◽  
Elias Balaras
Keyword(s):  
Reverse Flow ◽  
Leading Edge ◽  
Suction Side ◽  
Secondary Flows ◽  
Vaned Diffuser ◽  
Flow Rates ◽  
Turbulent Statistics ◽  
Large Eddy ◽  
Radial Pump ◽  
Reduced Flow

Turbopumps operating at reduced flow rates experience significant separation and backflow phenomena. Although Reynolds-Averaged Navier–Stokes (RANS) approaches proved to be usually able to capture the main flow features at design working conditions, previous numerical studies in the literature verified that eddy-resolving techniques are required in order to simulate the strong secondary flows generated at reduced loads. Here, highly resolved large-eddy simulations (LES) of a radial pump with a vaned diffuser are reported. The results are compared to particle image velocimetry (PIV) experiments in the literature. The main focus of the present work is to investigate the separation and backflow phenomena occurring at reduced flow rates. Our results indicate that the effect of these phenomena extends up to the impeller inflow: they involve the outer radii of the impeller vanes, influencing significantly the turbulent statistics of the flow. Also in the diffuser vanes, a strong spanwise evolution of the flow has been observed at the reduced load, with reverse flow, located mainly on the shroud side and on the suction side (SS) of the stationary channels, especially near the leading edge of the diffuser blades.

Representing rectangular jet dynamics through azimuthal Fourier modes

2021 ◽  
Vol 6 (7) ◽  
Author(s):  
Surya Chakrabarti ◽  
Datta Gaitonde ◽  
S. Unnikrishnan
Keyword(s):  
Rectangular Jet

scholarly journals Turbulent statistics and intermittency enhancement in coflowing superfluidHe4

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
L. Biferale ◽  
D. Khomenko ◽  
V. L'vov ◽  
A. Pomyalov ◽  
I. Procaccia ◽  
...  
Keyword(s):  
Turbulent Statistics

Flow structure within a heated rectangular jet ejector

1984 ◽  
Author(s):  
B. MCLACHLAN ◽  
A. KROTHAPALLI ◽  
K. NAGARAJA
Keyword(s):  
Flow Structure ◽  
Rectangular Jet

scholarly journals Influence of the Atmospheric Surface Layer on a Turbulent Flow Downstream of a Ship Superstructure

2013 ◽  
Vol 30 (8) ◽  
pp. 1803-1819 ◽  
Author(s):  
Luksa Luznik ◽  
Cody J. Brownell ◽  
Murray R. Snyder ◽  
Hyung Suk Kang
Keyword(s):  
Surface Layer ◽  
Atmospheric Surface Layer ◽  
The United States ◽  
Naval Academy ◽  
Mean Flow ◽  
Flow Distortion ◽  
Turbulent Statistics ◽  
Sonic Anemometers ◽  
Flight Deck ◽  
Inflow Conditions

Abstract This paper describes a set of turbulence measurements at sea in the area of high flow distortion in the near-wake and recirculation zone behind a ship's superstructure that is similar in geometry to a helicopter hangar/flight deck arrangement found on many modern U.S. Navy ships. The instrumented ship is a 32-m-long training vessel operated by the United States Naval Academy that has been modified by adding a representative flight deck and hangar structure. The flight deck is instrumented with up to seven sonic anemometers/thermometers that are used to obtain simultaneous velocity measurements at various spatial locations on the flight deck, and one sonic anemometer at bow mast is used to characterize inflow atmospheric boundary conditions. Data characterizing wind over the deck at an incoming angle of 0° (head winds) and wind speeds from 2 to 10 m s−1 obtained in the Chesapeake Bay are presented and discussed. Turbulent statistics of inflow conditions are analyzed using the Kaimal universal turbulence spectral model for the atmospheric surface layer and show that for the present dataset this approach eliminates the need to account for platform motion in computing variances and covariances. Conditional sampling of mean flow and turbulence statistics at the flight deck indicate no statistically significant variations between unstable, stable, and neutral atmospheric inflow conditions, and the results agree with the published data for flows over the backward-facing step geometries.

Hyperkinetic deposition of nanopowders by supersonic rectangular jet impingement

2001 ◽  
Vol 44 (8-9) ◽  
pp. 2179-2182 ◽  
Author(s):  
V Shukla ◽  
G.S Elliott ◽  
B.H Kear ◽  
L.E McCandlish
Keyword(s):  
Jet Impingement ◽  
Rectangular Jet

Characterization of Geometrical and Temporal Properties of Large-scale Motions in Turbulent Flows

2021 ◽  
Author(s):  
Christina Tsai ◽  
Kuang-Ting Wu
Keyword(s):  
Turbulent Flow ◽  
Turbulent Flows ◽  
Coherent Structures ◽  
Large Scale ◽  
Streamwise Velocity ◽  
Turbulent Structures ◽  
Temporal Properties ◽  
Turbulent Statistics ◽  
Spatial Locations

<p>It is demonstrated that turbulent boundary layers are populated by a hierarchy of recurrent structures, normally referred to as the coherent structures. Thus, it is desirable to gain a better understanding of the spatial-temporal characteristics of coherent structures and their impact on fluid particles. Furthermore, the ejection and sweep events play an important role in turbulent statistics. Therefore, this study focuses on the characterizations of flow particles under the influence of the above-mentioned two structures.</p><div><span>With regard to the geometry of turbulent structures, </span><span>Meinhart & Adrian (1995) </span>first highlighted the existence of large and irregularly shaped regions of uniform streamwise momentum zone (hereafter referred to as a uniform momentum zone, or UMZs), regions of relatively similar streamwise velocity with coherence in the streamwise and wall-normal directions.  <span>Subsequently, </span><span>de Silva et al. (2017) </span><span>provided a detection criterion that had previously been utilized to locate the uniform momentum zones (UMZ) and demonstrated the application of this criterion to estimate the spatial locations of the edges that demarcates UMZs.</span></div><div> </div><div>In this study, detection of the existence of UMZs is a pre-process of identifying the coherent structures. After the edges of UMZs are determined, the identification procedure of ejection and sweep events from turbulent flow DNS data should be defined. As such, an integrated criterion of distinguishing ejection and sweep events is proposed. Based on the integrated criterion, the statistical characterizations of coherent structures from available turbulent flow data such as event durations, event maximum heights, and wall-normal and streamwise lengths can be presented.</div>

Three-dimensional Vortex structure of Rectangular Jet with Tapered Triangular Tubes at Nozzle Four Corners

2021 ◽  
Vol 2021.58 (0) ◽  
pp. F023
Author(s):  
Naoki KAJITANI ◽  
Takahiro KIWATA ◽  
Takaaki KONO ◽  
Nobuyoshi KOMATSU ◽  
Riku OUCHI
Keyword(s):  
Vortex Structure ◽  
Three Dimensional ◽  
Rectangular Jet ◽  
Four Corners
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