Tidal turbines operate in unsteady flow environments that prompt complex flow interactions and challenge the validity of existing computational modelling methods. In this study, four numerical models of varying fidelity will be used to simulate a horizontal-axis tidal turbine under small-amplitude axial flow oscillations across a range of frequencies. The objective of the study is to assess the effectiveness of the different numerical models in capturing unsteady flow effects, as well as gaining insights regarding the strengths and shortcomings of each method. Smyth et al. (2024) tested three numerical models for their ability to capture unsteady loads of a tidal turbine: the 2D analytical Theodorsen function, a 3D vortex lattice method and a full 3D viscous URANS blade resolved simulation. While the two 3D models behaved similarly, the 2D Theodorsen function failed to accurately capture the unsteady flow behavior at low gust frequencies, further highlighting the importance of the 3D wake in unsteady load prediction. In this work, we will incorporate the actuator line model (ALM) to the comparison described above. The ALM is capable of generating a vortical wake, which Smyth et al. (2021) demonstrated is critical for the prediction of the loading response of horizontal axis turbines in uniform gusts, however, user defined parameters such as two-dimensional aerofoil data, the flow sampling method and the smearing radius, may affect the intensity of the turbine wake and its subsequent effect on the unsteady loads (Zormpa et al. (2024), Meyer-Forsting et al. (2019)). This study will explore the impact of those parameters and evaluate the ability of the ALM to capture unsteady flow effects at a range of gust frequencies. Comparing the ALM steady and unsteady loads with those from VLM and URANS simulations will provide valuable insights into the ALM's capabilities