Thermal Behaviour of the Residential Buildings with Cantilever Beam under Winter Day Boundary Conditions

  • Lutfu Namli Ondokuz Mayis University, Department of Mechanical Engineering, Samsun, Turkey


In this study, the thermal behaviour of the residential buildings with cantilever beam under winter day boundary conditions was investigated numerically by means of the open-ended structure approach. For this purpose, the parametric study has been realised for various ratios of cantilever beam depth/cantilever beam height (d/H) and Rayleigh numbers by using a computer program in case of no wind for laminar flow. Analyses were conducted for Rayleigh numbers which range from 10^3 and 10^6. The calculations were carried out for the ratios of d/H, namely 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0. The working fluid was handled as air (Pr=0.71). According to the findings; the mean Nu number along with the outer vertical wall (surface L) of the residential building, in general, decreases with increasing of d/H. This decreasing in the mean Nu number is evident for Ra≤10^4, but after Ra=10^5, it appears to be more pronounced. To have minimum heat loss from the residential building under winter day boundary condition, it is suggested that the ratio of d/H not be over 0.5 and at least 0.2.


LOpen-ended structure; Extended boundaries; Cantilever beam; Laminar natural convection

DOI: 10.17350/HJSE19030000090

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1. Raithby GD, Hollands KGT. Natural convection, in: Rohsenow WM, Harnett JP, Ganic EN, (Eds.), Handbook of Heat Transfer Fundamentals. second ed. McGraw-Hill, New York, 1985 (Chapter 6).

2. Ostrach O. Natural convection in enclosure, Journal of Heat Transfer 110 (1988) 1175-1190.

3. Tavares MCP, Goncalves HJP, Bastos JNTFC. The glazing area in residential buildings in temperate climate: The thermal-energetic performance of housing units in Lisbon. Energy and Buildings 140 (2017) 280–294.

4. Aimee Byrne A, Byrne G, O’Donnell G, Robinson A. Case studies of cavity and external wall insulation retrofitted under the Irish home energy saving scheme: Technical analysis and occupant perspectives. Energy and Buildings 130 (2016) 420–433.

5. Magalhaes SMC, Leal VMS, Horta IM. Modelling the relationship between heating energy use and indoor temperatures in residential buildings through artificial neural networks considering occupant behavior. Energy and Buildings 151 (2017) 332–343.

6. Yousefi F, Gholipour Y, Yan W. A study of the impact of occupant behaviors on energy performance of building envelopes using occupants’ data. Energy and Buildings 148 (2017) 182–198.

7. Jin X, Medina MA, Zhang X. On the placement of a phase change material thermal shield within the cavity of buildings walls for heat transfer rate reduction. Energy 73 (2014) 780-786.

8. Sorgato MJ, Melo AP, Lamberts R. The effect of window opening ventilation control on residential building energy consumption. Energy and Buildings 133 (2016) 1–13.

9. Selamet EE, Arpaci VS, Borgnakke C. Simulation of laminar buoyancy-driven flows in an enclosure. Numerical Heat Transfer, Part A 22 (1992) 401-420.

10. Chan YL, Tien CL. A numerical study of two-dimensional natural convection in square open cavities. Numerical Heat Transfer 8 (1985) 65-80.

11. Vafai K, Ettefagh J. The effect of sharp corners on buoyancy-driven flows with particular emphasis on outer boundaries. International Journal of Heat and Mass Transfer 33 (1990) 2311-2328.

12. Vafai K, Ettefagh J. Thermal and fluid flow instabilities in buoyancy-driven flows in open-ended cavities.
International Journal of Heat and Mass Transfer 33 (1990) 2329-2344.

13. Khanafer K, Vafai K, Lightston M. Mixed convection heat transfer in two-dimensional open-ended enclosures. International Journal of Heat and Mass Transfer 45 (2002) 5171-5190.

14. Elsayed MM, Chakroun W. Effects of aperture geometry on heat transfer in tilted partially open cavities. Journal of Heat Transfer 121 (1990) 819-827.

15. Khanafer K, Vafai K. Buoyancy-driven flows and heat transfer in open-ended enclosures: Elimination of the
extended boundaries. International Journal of Heat and Mass Transfer 43 (2000) 4087-4100.

16. Khanafer K, Vafai K. Effective boundary conditions for buoyancy-driven flows and heat transfer in fully open- ended two-dimensional enclosures. International Journal of Heat and Mass Transfer 45 (2002) 2527-2538.

17. Prianto E, Depecker P. Characteristic of airflow as the effect of balcony, opening design and internal division on indoor velocity: A case study of traditional dwelling in urban living quarter in tropical humid region, Energy and Building 34 (2002) 401-409.

18. Lai CM, Wang YH. Energy-saving potential of buildings envelope designs in residential houses in Taiwan. Energies 4 (2011) 2061-2076.

19. Chan ALS, Chow TT. Investigation on energy performance and energy payback period of application of balcony for residential apartment in Hong Kong. Energy and Building 42 (2010) 2400-2405.

20. Chand I, Bhargava PK, Krishak NLV. Effect of balconies on ventilation inducing aeromotive force on low-rise buildings. Building and Environment. 33 (1998) 385-396.

21. Namli L., Effects of built-in balcony on thermal performance in residential buildings: A case study. Journal of Building Physics 40(2) (2016) 125-143.

22. Roache PJ. Computational Fluid Dynamics. Hermosa, Albuquerque, NM, 1982.

23. Young D. Iterative methods for solving partial differential equations of elliptical type. Transactions of the AMS - American Mathematical Society 76 (1954) 92.A

24. Abu-Mulaweh HI, Armaly BF, Chen TS. Laminar natural convection flow over a vertical forward-facing step. Journal of Thermophysics and Heat Transfer 10 (1996) 517-523.

25. Asan H, Namli L. Laminar natural convection in a pitched roof of triangular cross-section: summer day boundary conditions. Energy and Building 33 (2000) 69-73.

26. Asan H, Namli L. Numerical simulation of buoyant flow in a roof of triangular cross-section under winter day boundary conditions, Energy and Building 33 (2001) 753-757.

27. Penot F. Numerical calculation of two-dimensional natural convection in isothermal open cavities. Numerical Heat Transfer 5 (1982) 421-437.

28. LeQuere O, Humphery JAC, Sherman FS. Numerical calculation of thermally driven two-dimensional unsteady laminar flow in cavities of rectangular cross-section. Numerical Heat Transfer 4 (1981) 249-283.
How to Cite
Namli, L. (1). Thermal Behaviour of the Residential Buildings with Cantilever Beam under Winter Day Boundary Conditions. Hittite Journal of Science & Engineering, 5(2), 155-164. Retrieved from