Multiphysics and uncertainty-aware dynamic modeling of pico-hydrokinetic turbine systems with wake effects

Articles in Press

Document Type : Research Article

Authors

Christophe Kikmo Wilba

Ekani Roger Yannick

Jean Pierre Ngoma

National Higher Polytechnic School of Douala, University of Douala, Cameroon.

10.22067/ijnao.2026.97659.1829

Abstract

This work proposes a coupled multiphysics framework for pico-hydrokinetic turbine systems operating under variable and uncertain flow conditions. The model brings together the incompressible Navier--Stokes equations for the fluid dynamics, a reduced-order description of rotor motion, and a simplified electrical conversion law, resulting in a coupled PDE--ODE system that captures the main interactions between fluid forcing, mechanical rotation, and energy extraction.
The resulting formulation is written as an evolution problem in a Hilbert phase space, where the dynamics are driven by a structured monotone operator combining a hydrodynamic component with mechanical-electrical dynamics and wake-induced coupling effects. The framework is consistent with classical incompressible flow theory and monotone operator structures, while keeping the modelling assumptions explicitly stated, so as to remain valid within the regimes covered by the underlying hypotheses.
Wake effects are introduced through a reduced actuator-disk-type representation of Jensen form, embedded directly into the coupled system in order to maintain a coherent link between velocity deficit, rotor response, and power production. Uncertain inflow conditions and parameter variations are represented in a parametric form, allowing a qualitative description of their influence on the overall system behaviour.
On the numerical side, a structure-preserving discretization is employed, based on a finite-dimensional monotone approximation in space combined with a backward Euler time integration. The computational results are assessed through comparison with a reduced reference model and published hydrokinetic data, with emphasis on the power coefficient, torque evolution, and optimal operating conditions.
The main contribution of this work lies in the consistent coupling of fluid, mechanical, and electrical dynamics within a unified monotone PDE--ODE framework, together with a clear and transparent formulation of assumptions, modelling limits, and numerical consistency. This provides a solid basis for further analytical developments and data-informed refinements in small-scale hydrokinetic energy systems.

Keywords

Multi-physics modeling

Pico-hydrokinetic turbine

Wake effect

Hydrodynamic uncertainties

Stability analysis

Subjects

• Modeling and Simulation

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