Numerical study on interactional aerodynamics of a quadcopter in hover with overset mesh in OpenFOAM

Park, Young Min; Jee, Solkeun

doi:10.1063/5.0160689

Cited by 4 publications

(1 citation statement)

References 26 publications

(62 reference statements)

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“…In Computational Fluid Dynamics (CFD), the availability of tools capable of simulating flows around moving bodies is of paramount importance. Simulation of moving bodies has been rigorously explored using both Eulerian [8][9][10] and Lagrangian [11] solvers. Moreover, dynamic mesh simulations have been successfully conducted through the integration of hybrid solvers.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Mesh Simulations in OpenFOAM: A Hybrid Eulerian–Lagrangian Approach

Pasolari,

Ferreira,

van Zuijlen

et al. 2024

Fluids

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The past few decades have witnessed a growing popularity in Eulerian–Lagrangian solvers due to their significant potential for simulating aerodynamic flows, particularly in cases involving strong body–vortex interactions. In this hybrid approach, the two component solvers are mutually coupled in a two-way fashion. Initially, the Lagrangian solver can supply boundary conditions to the Eulerian solver, while the Eulerian solver functions as a corrector for the Lagrangian solution in regions where the latter cannot achieve high accuracy. To utilize such tools effectively, it is vital for them to be capable of handling dynamic mesh movements. This study builds upon the previous research conducted by our team and extends the capabilities of the hybrid solver to handle dynamic meshes. While OpenFOAM, the Eulerian component of this hybrid code, incorporates built-in dynamic mesh properties, certain modifications are necessary to ensure its compatibility with the Lagrangian solver. More specifically, the evolution algorithm of the pimpleFOAM solver needs to be divided into two discrete steps: first, updating the mesh, and later, evolving the solution. This division enables a proper coupling between pimpleFOAM and the Lagrangian solver as an intermediate step. Therefore, the primary objective of this specific paper is to adapt the OpenFOAM solver to meet the demands of the hybrid solver and subsequently validate that the hybrid solver can effectively address dynamic mesh challenges using this approach. This approach introduces a pioneering method for conducting dynamic mesh simulations within the OpenFOAM framework, showcasing its potential for broader applications. To validate the approach, various test cases involving dynamic mesh movements are employed. Specifically, all these cases employ the Lamb–Oseen diffusing vortex, but each case incorporates different types of mesh movements, including translational, rotational, oscillational, and combinations thereof. The results from these cases demonstrate the effectiveness of the proposed OpenFOAM algorithm, with the maximum relative errors —when compared to the analytical solution across all presented cases—capped at 2.0% for the worst-case scenario. This affirms the algorithm’s capability to successfully handle dynamic mesh simulations with the proposed solver.

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Section: Introductionmentioning

confidence: 99%

Dynamic Mesh Simulations in OpenFOAM: A Hybrid Eulerian–Lagrangian Approach

Pasolari,

Ferreira,

van Zuijlen

et al. 2024

Fluids

View full text Add to dashboard Cite

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Interactional aerodynamics and acoustics of a rotor with an airframe in hover

Kim,

Hwang,

Myong

et al. 2024

Physics of Fluids

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The demand for the development of urban air mobility (UAM) powered by electric systems has been steadily rising across private and public sectors. Most UAM flights incorporate a distributed electric propulsion system to enhance aircraft safety and reliability, which entails an increase in the number of rotors or propellers. Consequently, aerodynamics and aeroacoustics are significantly influenced by strong interactions between the rotor and the airframe. In this study, we conducted a computational investigation to examine the impact of rotor–airframe interaction on aerodynamic and aeroacoustic characteristics. This examination considered variations in airframe shape and the distance between the rotor and airframe. The aerodynamic analysis was executed using the lattice-Boltzmann method simulation, in which acoustic predictions were made using the Ffowcs Williams–Hawkings(FW–H) acoustic analogy with a permeable surface. The airframe consists of two geometries: a cylinder and a cone. Tip vortex breakdown and the transition into the turbulent wake state were captured in both airframes, and a fountain flow was affected by the downwash circulation generated under certain proximity of airframe cases. The acoustic prediction results showed that high-intensity noise radiated over the broad surface of the airframe in the conical airframe case. Significant thrust force fluctuations and an increase in noise level were observed at the smallest rotor tip clearance, S/R=−0.1, compared to the isolated rotor. Furthermore, the noise contribution of the rotor and airframe was compared, revealing that the airframe noise level was even higher than the rotor noise at S/R=−0.1.

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Loads experienced by a Francis turbine during short and fast transient under part load operation

Zhou,

Dai,

Huang

et al. 2024

Physics of Fluids

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As hydropower is integrated into the renewable energy system, the turbine components are liable to many loads variation for regulation. The loads experienced under transient operation need to be accounted for and understood to develop adequate mitigation technique and strategies. To identify possible risks occurring during such short and fast transients, we investigate the nonlinear growth and time delay effects of pressure fluctuations, as well as the unsteady flow field evolution for a Francis turbine under load reduction in the part load regime. A two-stage transient process analytical framework is proposed via signal processing and vortex identification methods, including main transient and post-transient stages. In the main transient stage, the dominant frequency of pressure fluctuations within the draft tube shifts from 0.32·fn to 0.24·fn, accompanied by a fivefold increase in the amplitude. Furthermore, low-frequency pressure fluctuations in a wider range are identified (0–2·fn), source of possible resonance of power plant structures. The maximum pressure is reached in the post-transient stage after the end of the guide vane closure and is 50% larger than the maximum value in the main transient stage. When comparing the two components of pressure fluctuations within the draft tube, the synchronous component increases slowly but reaches the peak faster, which can be explained by the evolution of instantaneous vortex structure investigated with proper orthogonal decomposition. The findings are useful to ascertain possible risk factors along with the investigation of the evolution of non-stationary flow field in the context of frequent turbine load variations.

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Numerical study on interactional aerodynamics of a quadcopter in hover with overset mesh in OpenFOAM

Cited by 4 publications

References 26 publications

Dynamic Mesh Simulations in OpenFOAM: A Hybrid Eulerian–Lagrangian Approach

Dynamic Mesh Simulations in OpenFOAM: A Hybrid Eulerian–Lagrangian Approach

Interactional aerodynamics and acoustics of a rotor with an airframe in hover

Loads experienced by a Francis turbine during short and fast transient under part load operation

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