%X The application of vibration on a heated surface is found to be one of the promising cooling methods. Previous studies found that the thermal performance of the heated body depends on the vibrational characteristics and wave shape. However, for heat sinks, the direction of the vibration for different vibrational wave shapes has not been investigated, which may influence cooling. Thus, the current study conducted a numerical investigation to study the effect of the vibration direction of sinusoidal and square wave shaped vibration on the conventional heat sink and validated it against experimental results with a maximum deviation of 2.4. The study is conducted with a range of frequencies and peak-to-peak amplitude of 0-80 Hz and 0-0.005 m under the square and sinusoidal wave shapes. It was found that the Nusselt number increases with higher frequencies (f>40 Hz), and amplitudes and enhancement in Nusselt values are more dominant with square wave shapes. At the vibration frequency and peak-to-peak amplitude of 80 Hz and 0005 m, a maximum of 9.3 and 7.2 enhancement in the Nusselt number is recorded with square and sinusoidal vibration, respectively. Moreover, the result of the current study is compared with the published work, and it was concluded that the effect of vibration on heat transfer is superior to horizontal vibration in comparison with vertical vibration by 7 and 3.2 under square and sinusoidal wave shaped vibrations, respectively. © 2023, Semarak Ilmu Publishing. All rights reserved. %N 10 %R 10.37934/cfdl.15.10.170185 %D 2023 %L scholars18170 %J CFD Letters %O cited By 1 %A A.H.D.K. Rasangika %A M.S. Nasif %A W. Pao %A R. Al-Waked %V 15 %T CFD Investigation of the Effect of Vibration Direction on the Heat Transfer Enhancement of Heat Sink %P 170-185