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The flow and heat transfer of Al2O3–water nanofluid in a channel partially filled with porous media is investigated numerically. The turbulence effect in the porous media is taken under consideration in this article. A simple case is simulated first to evaluate the accuracy of the results in comparison with the available data. The turbulent kinetic energy profile is investigated at a flow cross section. The results show that the maximum turbulent kinetic energy occurs in the clear fluid region in the vicinity of the porous media region. The turbulent kinetic energy is a decreasing function of the porosity of the porous medium. The effect of porosity on the variation of turbulent kinetic energy decreases with the increase in the porosity of the porous medium. The turbulent kinetic energy in clear fluid and porous media regions decreases with the increase in nanofluid concentration from 0.01 to 0.03, and it increases with the increase in nanofluid concentration from 0.03 to 0.05. The temperature of the nanofluid increases with the increase in the nanofluid concentration and decrease in the porosity of porous media. It is shown that for this case, with the increase in nanofluid concentration and porosity of porous media, the skin friction coefficient increases and the Nusselt number decreases.

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In greenhouse horticulture, solar energy is the key to extending the greenhouse using seasonal or daily thermal storage technology and decreasing the energy consumption rate, especially in subtropical climate areas. Therefore, the present research aims to reach the optimal physical parameters of common greenhouses in northern areas of Iran to harness the best possible amount of solar energy in a year. Three common types of greenhouses, including even-span, modified arch and Quonset types, are considered. Threefloor area sizes are investigated for each shape to find the optimal physical parameters based on each greenhouse size. A mathematical model is proposed that uses the total solar fraction to compute the radiation