Experiments in Fluids

, Volume 18, Issue 5, pp 303–310 | Cite as

Azimuthal instability in an impinging jet: adiabatic wall temperature distribution

  • C. Meola
  • L. de Luca
  • G. M. Carlomagno
Originals
Received:
Accepted:

Abstract

The present work has been aimed at gaining some new insights into instability phenomena arising when an air jet impinges on a flat plate under certain conditions. At a critical Mach number, depending on the impingement distance, the jet loses its circumferential appearance with the formation of evenly equidistant azimuthal structures, whose number and location depend on the nozzle geometry and on the flow conditions. The instability is investigated in terms of pressure and adiabatic wall temperature; the latter is measured by means of an infrared scanning radiometer. Entrainment effects are found to play a key role in the priming and evolution of the instability.

Keywords

Temperature Distribution Mach Number Flow Condition Wall Temperature Flat Plate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

List of symbols

C1, C2, C3

circumferences over which structures are located

D

nozzle exit diameter [m or mm]

L

distance from plate to nozzle supporting flange [m]

M

Mach number

n

number of structures

p

local pressure [N m-2]

r

recovery factor

R

radial distance from jet center [m]

Re

Reynolds number, based on nozzle diameter, VD/v

T

temperature [K]

Taw

adiabatic wall temperature [K]

Tj

jet static temperature [K]

V

velocity at nozzle exit [m s-1]

Z

nozzle-to-plate distance [m]

Greek symbols

ɛ

emissivity coefficient

ν

kinematic viscosity [m2 s-1]

Subscripts

a

ambient

c

plate center

o

stagnation conditions

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Copyright information

© Springer-Verlag 1995

Authors and Affiliations

  • C. Meola
    • 1
  • L. de Luca
    • 1
  • G. M. Carlomagno
    • 1
  1. 1.Dipartimento di Energetica, Termofluidodinamica Applicata e Condizionamenti Ambientali (DETEC)Università degli Studi di Napoli “Federico II”NaplesItaly

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