With the advent of quadrotor unmanned aerial vehicles (UAV) becoming more prevalent for military and commercial applications, gaining a better understanding of their aerodynamic characteristics is critical. No matter the application, each operation begins and ends with vertical takeoff and landing (VTOL). Therefore, investigating the aerodynamic effects of ground proximity on thrust, wake, and vehicle stability is required to ensure safe operation. Based on previous use in published experimental studies, 0.240 m diameter rotor models with a rotation rate of 4860 RPM were used in the present work. A finite volume commercial Computational Fluid Dynamics (CFD) code STAR-CCM+ by Siemens was used to run three-dimensional implicit Unsteady Reynolds Averaged Navier-Stokes (URANS) simulations of a Da-Jiang Innovations (DJI) Phantom UAV utilizing dynamic meshing techniques for rotor motion and VTOL scenarios. Model validation was achieved by first simulating single and dual rotor cases to compare predictions of thrust and rotor-rotor interactions to published data. Following this, a full UAV was modeled in a hovering scenario far from solid boundaries to provide a baseline case. The single rotor simulation showed a 5.625% overshoot in thrust compared to an expected value of 3 N, and a 1.473% overshoot compared to a comparable published RANS simulation. At a minimum tip separation distance of 0.05D, a drop in time-averaged thrust of 1.256% and 1.186% was found for the dual rotor and baseline UAV cases compared to an expected drop of ~2%. Upon successfully validating the CFD simulation framework, the baseline UAV simulation was repeated for seven scenarios, having the UAV hover at heights between 3.0 m and ground level with a step change of 0.5 m. These simulations were used to compare how ground effect can change thrust and alter the wake formation. It was determined that ground effect was negligible beyond a height of 1.5 m for this UAV. Thus, the hovering cases beyond 1.5 m were omitted. Finally, a dynamic scenario was simulated having the UAV land from a height of 3.0 m, which was used to assess the stability of the UAV in VTOL by monitoring the pitching moment. Future work will be able to build from these simulations to create reduced order models and investigate more complex scenarios such as UAV ground vehicle wake interactions.