As marine and hydrokinetic (MHK) technologies which convert the flow of fluid into useful electrical power are developed, it is desirable to simulate drivetrain performance and refine control strategies in a laboratory prior to field installation. This paper presents and evaluates a technique developed to operate the prime mover of a dynamometer so that it drives a machine under test like an MHK turbine’s rotor. The approach utilizes environmental and rotor numerical models to calculate hydrodynamic torque. Relationships between shaft torque, shaft speed, and variable frequency drive native torque reference were used to modify torque reference settings to achieve actual emulated torque values. The accuracy at which physical shaft torque matches theoretical hydrodynamic torque was then evaluated for three basic operating states: locked rotor, spin up/down, and variable flow operation. Percent‐error of averaged measured and theoretical shaft torque during simulation of these states was 9.7%, 5.5%, and 5.2%, respectively, demonstrating the success of applying the proposed technique.