On turbulence production in a jet passing through a grid-type obstacle; An LES approach

Abe, Satoshi; Hirose, Yoshiyasu; Shibamoto, Yasuteru

Results in Engineering (Internet), 27, p.106307_1 - 106307_16, 2025/09

https://doi.org/10.1016/j.rineng.2025.106307

The interaction of turbulent jets plays a critical role in heat and mass transfer across a variety of engineering applications. In particular, the merging phenomena of jets in nuclear reactors are important for validating the credibility of the core exit temperature (CET) as an indicator of core heat-up. CET serves as a key criterion for accident management and ensuring the safe operation of the reactor. Understanding the dynamics of these jet interactions is essential for improving reactor safety and efficiency. Furthermore, in the field of containment thermal hydraulics during severe accidents, the behavior of a jet interacting with a grid-type obstacle has attracted significant attention. This study utilized Large Eddy Simulation (LES) to gain a deeper understanding of the flow characteristics of a jet affected by such an obstacle, with particular focus on the turbulence production mechanism. To improve the accuracy of turbulence modeling, the Coherent Structure Smagorinsky Model (CSM) was employed. Validation against experimental data confirmed that LES is a valuable tool for investigating jet flow behavior. The vortex structure of the jet was visualized using the Q-criterion. Additionally, the impact of the grid-type obstacle on the turbulence kinetic energy production rate was analyzed through radial profiles at various locations and its cumulative production.

A Systematic approach for the adequacy analysis of a set of experimental databases; Application in the framework of the ATRIUM activity

Baccou, J.*; Glantz, T.*; Ghione, A.*; Sargentini, L.*; Fillion, P.*; Damblin, G.*; Sueur, R.*; Iooss, B.*; Fang, J.*; Liu, J.*; et al.

Nuclear Engineering and Design, 421, p.113035_1 - 113035_16, 2024/05

https://doi.org/10.1016/j.nucengdes.2024.113035

Critical heat flux for downward flows in vertical round pipes

Hirose, Yoshiyasu; Shibamoto, Yasuteru; Hibiki, Takashi*

Progress in Nuclear Energy, 168, p.105027_1 - 105027_17, 2024/03

https://doi.org/10.1016/j.pnucene.2023.105027

Numerical analysis of natural convection behavior in density stratification induced by external cooling of a containment vessel

Ishigaki, Masahiro*; Abe, Satoshi; Hamdani, A.; Hirose, Yoshiyasu

Annals of Nuclear Energy, 168, p.108867_1 - 108867_20, 2022/04

https://doi.org/10.1016/j.anucene.2021.108867

Overview and main outcomes of the pool scrubbing lumped-parameter code benchmark on hydrodynamic aspects in IPRESCA project

Marchetto, C.*; Ha, K. S*; Herranz, L. E.*; Hirose, Yoshiyasu; Jankowski, T.*; Lee, Y.*; Nowack, H.*; Pellegrini, M.*; Sun, X.*

Proceedings of 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-19) (Internet), 17 Pages, 2022/03

The Dependence of pool scrubbing decontamination factor on particle number density; Modeling based on bubble mass and energy balances

Sun, Haomin; Shibamoto, Yasuteru; Hirose, Yoshiyasu; Kukita, Yutaka

Journal of Nuclear Science and Technology, 58(9), p.1048 - 1057, 2021/09

https://doi.org/10.1080/00223131.2021.1907254

no abstracts in English

Application of immersed boundary method for jet flow in grating type structure

Hirose, Yoshiyasu; Ishigaki, Masahiro; Abe, Satoshi; Shibamoto, Yasuteru

Proceedings of International Topical Meeting on Advances in Thermal Hydraulics (ATH 2020) (Internet), p.757 - 767, 2020/10

https://doi.org/10.13182/ATH2020-32837

Thin liquid film thickness measurement by ultrasound

Wada, Yuki; Sagawa, Jun*; Hirose, Yoshiyasu*; Satou, Akira; Shibamoto, Yasuteru; Yonomoto, Taisuke

no journal, , 

In this study, ultrasound liquid film thickness measurement system is developed to measure thin liquid film thickness using a piezo element of 15 MHz and an original driving circuit by the pulse-echo method. Since our system is higher frequency than previous study, we can observe individually multi-reflected signals in the liquid film until 0.2 mm thickness and it is indicated that high accuracy liquid film thickness measurement will be possible less than 0.2 mm thickness.

Data assimilation application to CFD simulation of thermal flow in a large containment vessel facility CIGMA

Ishigaki, Masahiro*; Hirose, Yoshiyasu; Abe, Satoshi; Nagai, Toru*; Watanabe, Tadashi*

no journal, , 

no abstracts in English

Application of data assimilation to flow analysis of a jet into a density stratified layer

Wada, Takayuki*; Ishigaki, Masahiro*; Hirose, Yoshiyasu

no journal, , 

no abstracts in English