Skip to main content

Heat transfer characteristics of single circular jet impinging on a flat surface with a protrusion


An experimental investigation of heat transfer from a single circular jet impinging normally on a flat plate with a protrusion of depth 1, 2 and 3 mm was carried out. The temperature was measured over a Reynolds number range of 10,000 to 33,000 and nozzle exit-to-plate spacing ranged from 2 to 10 jet diameters. The average heat transfer characteristics were compared with the results from the literature, and the agreements were good. Further, numerical simulations were performed using ANSYS Fluent 18.1 to compare the results with those from experiments. The results showed that the increase of jet Reynolds number and relative depth of protrusion enhances the heat transfer on the impinging surfaces up to 16.69% compared to a flat surface. The maximum increase in the Nusselt number occurs at a spacing of 5 jet diameters (nearly at the end of Potential core zone) and Reynolds number 33000 for all cases. Further, the average percentage change of Nusselt number over the Reynolds number range decreased from 9.74% to 4.73% as protrusion depth increases from 0 to 3 mm due to flow separation. The study of the effect of heat input on the heat transfer enhancement was carried out by comparing Nusselt number for heat supply values of 60 W and 90 W. For higher heat input (90 W) and longer stand-off distance (Z/d = 10) it was observed that the effects of weak impingement flow field are counter acted by natural convection plume flow emanating from the heated surface. Hence, in such cases, impingement cooling is not effective.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18
Fig. 19
Fig. 20
Fig. 21
Fig. 22
Fig. 23
Fig. 24
Fig. 25


A S :

Surface area of impingement plate [m2]

β :

Co-efficient of volume expansion [K−1]

d :

Diameter of jet nozzle [mm]

d or (∆T)Ref :

Temperature difference across laminar sublayer

D :

Diameter of protrusion [mm]

D h :

Hydraulic diameter of impinging surface [mm]

δ :

Depth of dome [mm]

d/D :

Diameter ratio

δ/D :

Protrusion relative depth

g :

Gravitational acceleration [m/s2]

Gr :

Grashof number

\( \overline{h} \) :

Average heat transfer coefficient [W/m2K]

K air :

Thermal conductivity of air [W/m K]

L c :

Characteristic length for horizontal surface [m]


Mach number

\( {\overline{Nu}}_o \) :

Average Nusselt number based on diameter of nozzle

\( {\overline{Nu}}_p \) :

Average Nusselt number based on diameter of impinging plate

ϑ :

Kinematic viscosity of air [m2/s]

P :

Power supplied from DC Power source [W]

Pr :

Prandtl number

Q Cond :

Conduction heat losses [W]

Q Conv :

Convection heat transfer from impingement plate [W]

Q Rad :

Radiation heat losses [W]

Q Supply :

heat supplied from power source [W]

q" :

Heat flux in [W/m2]

Ra :

Rayleigh number

Re :

Reynolds number

R :

Radial distance from stagnation point [mm]

T a :

Temperature of atmospheric air [°C]

T f :

Air film temperature [°C]

\( \overline{T_S} \) :

Average surface temperature of the impingement surface [°C]

T R :

Local temperature at thermocouple points from 0 to R [°C]

ϑ :

Non-dimensional temperature

U C :

Centre line velocity [m/s]

y 1/2 :

Half jet width [mm]

y+, u+ :

Dimensionless law of the wall variables


Jet axial distance [mm]

\( \raisebox{1ex}{${y}_{1/2}$}\!\left/ \!\raisebox{-1ex}{$Z$}\right. \) :

Jet spread rate


  1. Dewan A et al (2004) Proceedings of the institution of mechanical engineers. Part A: Journal of Power and Energy 218(7):509–527

    Google Scholar 

  2. Gau C, Sheu WY, Shen CH (1997) Impingement cooling flow and heat transfer under acoustic excitations. J Heat Transf 119:810

    Article  Google Scholar 

  3. Hrycak P (1983) Heat transfer from round impinging jets to a flat plate. International Journal Heat and Mass Transfer 26(12):1857–1865

    Article  Google Scholar 

  4. Huang L, El-Genk MS (1994) Heat transfer of an impinging jet on a flat surface. Int J Heat Mass Transf 37(13):1915–1923

    Article  Google Scholar 

  5. Beitelmal AH, Saad MA, Patel CD (2000) Effects of surface roughness on the average heat transfer of an impinging air jet. Int.Comm. Heat Mass Transfer 27(1):1–12

    Article  Google Scholar 

  6. Celik N (2011) Effects of the surface roughness on heat transfer of perpendicularly impinging co-axial jet. Heat and Mass Transfer journal 47:1209–1217

    Article  Google Scholar 

  7. Zhang D et al (2013) Flow and heat transfer characteristics of single jet impinging on protrusioned surface. Int J Heat Mass Transf 58:18–28

    Article  Google Scholar 

  8. Gau C, Chung CM (1991) Surface curvature effect on slot-air-jet impingement cooling flow and heat transfer process. J Heat Transf 113:858

    Article  Google Scholar 

  9. Gau C, Lee CC (1992) Impingement cooling flow structure and heat transfer along rib-roughened walls. Int J Heat Mass Transf 35(11):3009–3020

    Article  Google Scholar 

  10. Gau C, Lee IC (2000) Flow and impingement cooling heat transfer along triangular rib roughened walls. Int J Heat Mass Transf 43:4405–4418

    Article  Google Scholar 

  11. Hansen LG, Webb BW (1993) Air jet impingement heat transfer from modified surfaces. Int J Heat Mass Transf 36(4):989–997

    Article  Google Scholar 

  12. Fleischer AS, Nejad SR (2004) Jet impingement cooling of a discretely heated portion of a protruding pedestal with a single round air jet. Exp Thermal Fluid Sci 28:893–901

    Article  Google Scholar 

  13. Chang SW, Chiou SF, Chang SF (2007) Heat transfer of impinging jet array over concave- dimpled surface with applications to cooling of electronics chipsets. Exp Thermal Fluid Sci 31:625–640

    Article  Google Scholar 

  14. Katti V, Prabhu SV (2008) Heat transfer enhancement on a flat surface with axisymmetric detached ribs by normal impingement of circular air jet. International journal of Heat and Fluid Flow 29:1279–1294

    Article  Google Scholar 

  15. Spring S, Xing Y, Weigand B (2012) An experimental and numerical study of heat transfer from arrays of impinging jets with surface ribs. Journal of Heat Transfer 134(8):082201–1 to11

    Article  Google Scholar 

  16. Caliskan S, Baskaya S (2012) Experimental investigation of impinging jet array heat transfer from a surface with V-shaped and convergent-divergent ribs. International Journal of Thermal Sciences 59:234–246

    Article  Google Scholar 

  17. Sharif MAR, Ramirez NM (2013) Surface roughness effects on the heat transfer due to turbulent round jet impingement on convex hemispherical surfaces. Applied Thermal Engineering 51:1026–1037

    Article  Google Scholar 

  18. Wan C, Rao Y, Chen P (2015) Numerical predictions of jet impingement heat transfer on square pin-fin roughened plates. Appl Therm Eng 80:301–309

    Article  Google Scholar 

  19. Dobbertean MM, Rahman MM (2016) Numerical analysis of steady heat transfer for jet impingement on patterned surfaces. Appl Therm Eng 103:481–490

    Article  Google Scholar 

  20. Silva C, Marotta E, Fletcher L (2007) Flow structure and enhanced heat transfer in channel flow with dimpled surfaces: application to heat sinks in microelectronic cooling. J Electron Packag 129(2):157–166

    Article  Google Scholar 

  21. Ligrani PM, Ren Z, Buzzard WC (2017) Impingement jet array heat transfer with small-scale cylinder target surface roughness arrays. Int J Heat Mass Transf 10:895–905

    Article  Google Scholar 

  22. Mi J, Kalt P, Nathan GJ (2010) On turbulent jets issuing from Notched-Rectangular and circular orifice plates. Journal of Flow Turbulence Combust 84:565–582

    Article  Google Scholar 

  23. CUSAT, Jet Theory, Chapter 2, Division of Safety and Fire Engineering

  24. Cengel YA, Ghajar AJ (2013) Heat and mass transfer (fundamentals and applications), Fourth edition. Tata McGraw Hill Education Private Limited, New Delhi

    Google Scholar 

  25. Holman JP (1984) Experimental methods for engineers. McGraw-Hill, New York

    Google Scholar 

  26. Martin H (1977) Heat and mass transfer between impinging gas jets and solid surfaces. Adv in Heat Transfer 13:1–60

    Article  Google Scholar 

  27. J. N. B. Livingood and P. Hrycak, Impingement heat transfer from turbulent air jets to flat plates, Lewis Research Center, Cleveland, Ohio. 1973, Report No. NASA TM X- 2778

  28. Cengel YA, Cimbala JM (2013) Fluid mechanics (fundamentals and applications), Second edition. Tata McGraw Hill Education Private Limited, New Delhi

    Google Scholar 

Download references

Author information

Authors and Affiliations


Corresponding author

Correspondence to K Srinivasan.

Additional information

Publisher’s note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Nagesha, K., Srinivasan, K. & Sundararajan, T. Heat transfer characteristics of single circular jet impinging on a flat surface with a protrusion. Heat Mass Transfer 56, 1901–1920 (2020).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: