TiO2-water nanofluid within a tilted triangular enclosure including a square heater: optimum heat transferKarim Ragui, Abdelkader Boutra, Youb Khaled Benkahla, Nabila Labsi and M’barek FeddaouiMechanics & Industry, 17 6 (2016) 612DOI: https://doi.org/10.1051/meca/2016009