Turbulence Models for Turbomachinery

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Energy Systems".

Deadline for manuscript submissions: 10 September 2025 | Viewed by 2883

Special Issue Editors


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Guest Editor
Hydraulic Machinery and Energy Systems, Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, 11120 Belgrade, Serbia
Interests: hydraulic machines; energy systems; experimental investigation of turbulence; particle image velocimetry (PIV); energy efficiency
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Guest Editor
Department of Aerospace Engineering, Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, 11120 Belgrade, Serbia
Interests: computational aerodynamics; turbulence; rotor aerodynamics; aircraft design; aircraft optimization

Special Issue Information

Dear Colleagues,

Turbulent flow, characterized by chaotic changes in velocity and pressure, is still an unsolved problem. It occupies the attention of numerous researchers in theoretical and applied physics worldwide. The Kolmogorov turbulence theory, as a set of hypotheses, is one of a few great steps in the direction of revealing turbulence. However, a general theory of turbulence still does not exist.

Turbomachinery are the most used machines in all areas. They exist in almost every engineering system. Carrying out research on turbulence in these rotating systems is quite a challenging task. Numerous experimental techniques are applied in the complex research of turbulence in turbomachinery, from classical ones to the novel ones, such as the following:

  • Fast-response multihole probes;
  • Three-component velocimetry systems;
  • High-speed stereo particle image velocimetry;
  • Holographic particle image velocimetry.

On the basis of the acquired experimental data, numerous turbulence models for flows in turbomachinery can be developed and tested, with the roles of the RANSs (Reynolds-averaged Navier–Stokes equations), LESs (large eddy simulations), hybrid RANS-LES modeling, DNSs (direct numerical simulations), and data-driven turbulence modeling in turbomachinery industry having great importance and potential.

Thus, this Special Issue will present a discussion on various turbomachinery geometries (radial, diagonal, axial) inbuilt in pipes, diffusers, jets, etc.

Prof. Dr. Djordje Cantrak
Dr. Jelena Svorcan
Guest Editors

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Keywords

  • turbulence
  • turbomachinery
  • RANS
  • LES
  • hybrid RANS-LES
  • DNS
  • AI

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Published Papers (3 papers)

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Research

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14 pages, 5565 KiB  
Article
Experimental and Numerical Research on Swirl Flow in Straight Conical Diffuser
by Dejan Ilić, Jelena Svorcan, Đorđe Čantrak and Novica Janković
Processes 2025, 13(1), 182; https://doi.org/10.3390/pr13010182 - 10 Jan 2025
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Abstract
The main objective of the current study is a detailed (both numerical and experimental) investigation of the highly unsteady and complex swirl flow in a straight conical diffuser (with a total divergence angle of 8.6°) generated by an axial fan impeller. Pressure, and [...] Read more.
The main objective of the current study is a detailed (both numerical and experimental) investigation of the highly unsteady and complex swirl flow in a straight conical diffuser (with a total divergence angle of 8.6°) generated by an axial fan impeller. Pressure, and axial and tangential velocity profiles along several cross-sections were measured by original classical probes in two different flow regimes at the inlet: the modified solid body type of moderate swirl and the solid body type of strong swirl and reverse flow; they were additionally confirmed/validated by laser Doppler anemometry measurements. Computational studies of spatial, unsteady, viscous, compressible flows were performed in ANSYS Fluent by large eddy simulation. The fan was neglected, and its effect was replaced by the pressure and velocity profiles assigned along the inlet and outlet boundaries. The two sets of data obtained were compared, and several conclusions were drawn. In general, the relative errors of the pressure profiles (2–5%) were lower than the observed discrepancies in the axial velocity profiles (5–40% for the first and 15–50% for the second flow regime, respectively). The employed reduced numerical model can be considered acceptable since it provides insights into the complexity of the investigated swirl flow. Full article
(This article belongs to the Special Issue Turbulence Models for Turbomachinery)
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16 pages, 8867 KiB  
Article
Experimental Analysis of Acoustic Spectra for Leading/Trailing-Edge Serrated Blades in Cascade Configuration
by Andrei-George Totu, Marius Deaconu, Laurențiu Cristea, Alina Bogoi, Daniel-Eugeniu Crunțeanu and Grigore Cican
Processes 2024, 12(11), 2613; https://doi.org/10.3390/pr12112613 - 20 Nov 2024
Cited by 1 | Viewed by 941
Abstract
This study aims to highlight the noise reduction achieved through the integration of serrated blades on the leading and trailing edges within a small-scale cascade configuration relevant to turbomachinery contexts. Experiments were conducted using a newly developed 3D-printed test bench, enabling both acoustic [...] Read more.
This study aims to highlight the noise reduction achieved through the integration of serrated blades on the leading and trailing edges within a small-scale cascade configuration relevant to turbomachinery contexts. Experiments were conducted using a newly developed 3D-printed test bench, enabling both acoustic and aerodynamic measurements. Turbulence was generated using a rectangular grid positioned at two axial locations. Non-dimensional spectra were computed and compared with experimental data, showing good agreement over a wide frequency range. Significant noise reduction was observed in the 1000–3000 Hz band, despite the lack of optimization of turbulence and serration parameters. Leading-edge serrations were found to be effective at lower frequencies in the axial direction and at higher frequencies laterally. In contrast, trailing-edge serrations had a minimal impact above 3500 Hz, performing worse than the reference condition across a large frequency range. Nevertheless, for this initial iteration at a small scale, overall sound pressure level reductions of up to 1 dB were achieved with trailing-edge serrations and up to 1.5 dB with leading-edge serrations, underscoring their potential for noise mitigation in relevant applications. Full article
(This article belongs to the Special Issue Turbulence Models for Turbomachinery)
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Review

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63 pages, 18507 KiB  
Review
Insights from the Last Decade in Computational Fluid Dynamics (CFD) Design and Performance Enhancement of Darrieus Wind Turbines
by Saïf ed-Dîn Fertahi, Shafiqur Rehman, Ernesto Benini, Khadija Lahrech, Abderrahim Samaouali, Asmae Arbaoui, Imad Kadiri and Rachid Agounoun
Processes 2025, 13(2), 370; https://doi.org/10.3390/pr13020370 - 28 Jan 2025
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Abstract
This review provides an analysis of advancements in the design and performance assessment of Darrieus wind turbines over the past decade, with a focus on the contributions of computational fluid dynamics (CFD) to this field. The primary objective is to present insights from [...] Read more.
This review provides an analysis of advancements in the design and performance assessment of Darrieus wind turbines over the past decade, with a focus on the contributions of computational fluid dynamics (CFD) to this field. The primary objective is to present insights from studies conducted between 2014 and 2024, emphasizing the enhancement of Darrieus wind turbine performance through various technological innovations. The research methodology employed for this review includes a critical analysis of published articles related to Darrieus turbines. The focus on the period from 2014 to 2024 was considered to highlight recent parametric CFD studies on Darrieus turbines, avoiding overlap with previously published reviews and maintaining originality relative to existing review works in the literature. By synthesizing a collection of articles, the review discusses a wide range of recent investigations utilizing CFD modeling techniques, including both 2D and 3D simulations. These studies predominantly utilize the “Ansys-Fluent” V12.0 and “STAR CCM+” V9.02 solvers to evaluate the aerodynamic performance of Darrieus rotors. Technological advancements focus on modifying the geometry of Darrieus, including alterations to blade profiles, chord length, rotor diameter, number of blades, turbine height, rotor solidity, and the integration of multiple rotors in various configurations. Additionally, the incorporation of flow deflectors, the use of advanced blade shapes, such as V-shaped or twisted blades, and the application of an opening ratio on the blades are explored to enhance rotor efficiency. The review highlights the significant impact of these geometric modifications on key performance metrics, particularly the moment and power coefficients. A dedicated section presents CFD-derived visualizations, including vorticity fields, turbulence contours illustrated through the Q-criterion, velocity vectors, and dynamic pressure contours. These visualizations provide a description of the flow structures around the modified Darrieus rotors. Moreover, the review includes an analysis of the dynamic performance curves of Darrieus, which show improvements resulting from the modifications of the baseline design. This analysis covers the evolution of pressure coefficients, moment coefficients, and the increased power output of Darrieus. Full article
(This article belongs to the Special Issue Turbulence Models for Turbomachinery)
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