## THERMAL SCIENCE

International Scientific Journal

### Thermal Science - Online First

online first only
### Heat and mass transfer effects on natural convection flow along a horizontal triangular wavy surface

**ABSTRACT**

An analysis is carried out to thoroughly understand the characteristics of fluid flow, heat transfer and mass transfer for the natural convection boundary layer flow along a triangular horizontal wavy surface. Combine buoyancy driven boundary layer equations for the flow are switched into convenient form via coordinate transformations. Full nonlinear equations are integrated numerically for Pr = 0.051. Interesting results for the uneven surface are found which are expressed in the form of wall shear stress, rate of heat transfer and rate of mass transfer. Solutions are also visualized via streamlines, isotherms and isolines for concentration. Computational results certify that, shear stress, temperature gradient and concentration gradient enhances as soon as the amplitude of the wavy surface, a, increases, but complex geometry do not allow to carry simulations for a >1.5. This factor probably ensures that sinusoidal waveform is better than triangular waveform.

**KEYWORDS**

PAPER SUBMITTED: 2015-07-22

PAPER REVISED: 2016-03-22

PAPER ACCEPTED: 2016-04-23

PUBLISHED ONLINE: 2016-05-08

- Yao, L. S., Natural convection along a vertical wavy surface, ASME Journal of Heat Transfer, 105 (1983), pp. 465-468.
- Moulic, S. G. and Yao, L. S., Natural convection along a wavy surface with uniform heat flux, ASME Journal of Heat Transfer, 111 (1989), pp. 1106-1108.
- Moulic, S. G. and Yao, L. S., Mixed convection along wavy surface, ASME Journal of Heat Transfer, 111 (1989), pp. 974-979.
- Rees, D. A. S., and Pop, I., Free convection induced by a horizontal wavy surface in a porous medium, Fluid Dynamics Research, 14 (1994), pp. 151-166.
- Hossain, M. A., and Pop, I., Magnetohydrodynamic boundary layer flow and heat transfer on a continuous moving wavy surface, Archives of Mechanics, 48 (1996), pp. 813-823.
- Hossain, M. A., and Rees, D. A. S., Combined heat and mass transfer in natural convection flow from a vertical wavy surface, Acta Mechanica, 136 (1999), pp. 133-141.
- Hossain, Md. A., et al., Natural convection with variable viscosity and thermal conductivity from a vertical wavy cone, International Journal of Thermal Sciences, 40 (2001), pp. 437-443.
- Jang, J. H., and Yan, W. M., Mixed convection heat and mass transfer along a vertical wavy surface, International Journal of Heat and Mass Transfer, 47 (2004), pp. 419-428.
- Molla, M. M., and Hossain, M. A., Radiation effect on mixed convection laminar flow along a vertical wavy surface, International Journal of Thermal Sciences, 46 (2007), pp. 926-935.
- Molla, M. M., et al., Natural convection flow along a vertical complex wavy surface with uniform heat flux, ASME Journal of Heat Transfer, 129 (2007), pp. 1403-1407.
- Yau, Her-Terng, et al., A numerical investigation into electroosmotic flow in microchannels with complex wavy surfaces, Thermal Science, 15 (2011), pp. S87-S94.
- Narayana, M., et al., On double-diffusive convection and cross diffusion effects on a horizontal wavy surface in a porous medium, Boundary Value Problems, 88 (2012), pp. 1-22.
- Siddiqa, S., and Hossain, M. A., Natural convection flow over wavy horizontal surface, Advances in Mechanical Engineering, 2013 (2013), Article ID 743034, pp. 1-7.
- Bahaidarah, H. M. S., and Sahin, A. Z., Thermodynamic analysis of fluid flow in channels with wavy sinusoidal walls, Thermal Science, 17 (2013), pp. 813-822.
- Siddiqa, S., et al., The effect of thermal radiation on the natural convection boundary layer flow over a wavy horizontal surface, International Journal of Thermal Sciences, 84 (2014), pp. 143-150.
- Xiaohong, G., et al., Analysis of three dimensional flow and heat transfer in a cross wavy primary surface recuperator for a microturbine system, Thermal Science, 19 (2015), pp. 489-496.
- Parvin, S., et al., MHD mixed convection heat transfer through vertical wavy isothermal channels, International Journal of Energy and Technology, 34 (2011), pp. 1-9.
- Nasrin, R., et al., Combined convection flow in triangular wavy chamber filled with water-CuO nanofluid: effect of viscosity models, International Communications in Heat and Mass Transfer, 39 (2012), pp. 1226-1236.
- Siddiqa, S., et al., Natural convection flow of viscous fluid over triangular wavy horizontal surface, Computers & Fluids, 106 (2015.), pp. 130-134.
- Gebhart B., and Pera, L., The nature of vertical natural convection flows resulting from the combined buoyancy effects of thermal and mass-diffusion, International Journal of Heat and Mass Transfer, 14 (1971), pp. 2025-2050.
- Pera, L., and Gebhart B., Natural convection flows adjacent to horizontal surfaces resulting from the combined buoyancy effects of thermal and mass diffusion, International Journal of Heat and Mass Transfer, 15 (1972), pp. 269-278.
- Gebhart B., et al., Buoyancy-induced flow and transport, Wishington: Hemisphere, 1988.
- Khair K. R., and Bejan, A., Mass transfer to natural convection boundary layer flow driven by heat transfer, International Journal of Heat and Mass Transfer, 30 (1985), pp. 369-376.
- Lin, H. T., and Wu, C.-M., Combined heat and mass transfer by laminar natural convection from a vertical plate, International Journal of Heat and Mass Transfer, 30 (1995), pp. 369-376.
- Lin, H. T., and Wu, C.-M., Combined heat and mass transfer by laminar natural convection from a vertical plate with uniform heat flux and concentrations, International Journal of Heat and Mass Transfer, 32 (1997), pp. 293-299.
- Mongruel, A., et al., Scaling of boundary layer flows driven by double- diffusive convection, International Journal of Heat and Mass Transfer, 39 (1996), pp. 3899-3910.
- Garooshi, F., et al., Mixture modeling of mixed convection of nanofluids in a square cavity with internal and external heating, Powder Technology, 275 (2015), pp. 304-321.
- Blotter, F. G., Finite difference method of solution of boundary layer equations, AIAA Journal, 8 (1970), pp. 193-205.