The Investigation of the Riemann-Liouville Fractional Operator on Natural Convective Fluid Flow in a Vertical Cylindrical Material with Variable Viscosity. IJDM [Internet]. 2026 Jun. 12 [cited 2026 Sep. 22];3(2):140-53. Available from: https://ijdm.org.ng/index.php/Journals/article/view/342