Numerical study of the impact of water injection holes arrangement on cavitation flow control

Water literacy has become a fundamental aspect in today’s society, as its conservation, preservation and management is key to ensuring human survival. The purpose of this paper was to analyze the effectiveness of flipped learning methodology on a traditional training practice in water literacy at the first level of secondary education. The flipped learning method consisted in providing the contents to the students before the class sessions, encouraging an active learning. A descriptive study was adopted with two experimental groups, two control groups and only post-test. An ad hoc questionnaire was used as an instrument to measure the parameters: Socio-educational, Motivation, Interactions, Autonomy, Collaboration; Deepening of contents; Problem solving, Class time and Ratings. The final sample was composed of 120 students, divided into four groups of 30 students each. The application of the treatment in the experimental groups lasted 10 sessions of 55 min. The results indicate that the use of time in class, the autonomy and the deepening of the contents were the aspects that improved most with the flipped learning approach. However, no significant differences in ratings were found. Finally, the main findings and their implications for water literacy are discussed.

Section: Introductionmentioning

confidence: 99%

Flipped Learning Approach as Educational Innovation in Water Literacy

Moreno-Guerrero

Rodríguez

Belmonte

et al. 2020

“…We agree with [96] on the need to develop curricula that more explicitly address the interconnectedness of different aspects of sustainable development and that use pedagogies that help students act on these challenges. Teaching and learning processes should make students aware of water issues in all their dimensions [97], as students strongly associate sustainability with environmental aspects and neglect the economic, social and cultural dimensions [96]. In this sense, the curricular elements of the areas intended for water education should also be oriented towards other issues.…”

Section: Need To Improve the Curriculum And Of New Approachesmentioning

confidence: 99%

Water from the Perspective of Education for Sustainable Development: An Exploratory Study in the Spanish Secondary Education Curriculum

Martínez‐Borreguero

Maestre-Jiménez

Mateos-Núñez

et al. 2020

Current educational curricula in Spain contain few references to sustainability topics, so there is insufficient coverage of these issues in the classroom. Notably, there is a lack of reference to the concept of water from a sustainable perspective. The key aim of this study was to analyze the presence of the concept of water in the curriculum that regulates secondary education in Spain using a previously established system of categories. An exploratory and descriptive research methodology was followed, in which we carried out a qualitative lexicographical analysis of the concept of water in the Spanish secondary education curriculum. An analysis of the cognitive demand required of students to learn about water, according to Bloom’s taxonomy, was also conducted. The results show that the concept of water appears moderately in the curriculum focusing on some aspects of Sustainable Development. Likewise, the analysis of the cognitive demand required of students for learning about water reveals that lower levels of knowledge and comprehension predominate based on Bloom’s taxonomy. We consider that teaching water from a sustainable perspective can generate in students awareness and values about nature and the environment, knowledge that contributes to sensible use of water and involvement for sustainable development.

“…Zhi et al [13] numerically investigated the unstable vaporous cavities around a surface-piercing hydrofoil using the large-eddy simulation coupled with the Schnerr-Sauer cavitation model, and the results could contribute to the novel hydrofoil designs and their flow control. Wang et al [14] presented a method of water injection to the flow field using distributed holes on the suction surface of a hydrofoil to control cavitation flow, which will facilitate development of engineering designs. Sun et al [15] numerically studied the cavitating flow fields of a NACA 66 rigid hydrofoil and flexible hydrofoil, and used dynamic mode decomposition to capture the flow field modal characteristics.…”

Section: Introductionmentioning

confidence: 99%

Study on Cascade Density of the Impeller Based on Response Surface Analysis

Gao,

Cheng

2023

In order to improve the cavitation performance of hydraulic machinery in the design stage, the response surface analysis method is used to study the influence of cascade density on the hydraulic characteristics and cavitation characteristics of a three-dimensional rotating hydrofoil. For this method, an axial flow impeller with a specific speed of 750 is selected as the experimental object. Nine groups of three-dimensional rotating hydrofoils with different cascade densities were designed by the D-optimal quadratic sampling method. The impeller and guide vane were structured and meshed by TurboGrid. The inlet and outlet extension sections were structured and meshed by ICEM. Grid independence analysis was carried out. The hydraulic characteristics and cavitation characteristics of nine groups of hydrofoils were calculated by CFD numerical simulation. The calculation results of nine groups of schemes were analyzed from three angles of external characteristics, flow pattern and cavitation performance, and the better schemes under each analysis angle were obtained. By means of response surface analysis, more external characteristics and cavitation characteristics of different cascade densities will be filled. Finally, combined with the response target, the influence of cascade density on each target is analyzed and the comprehensive selection range of hub and shroud is given. This method can improve the rationality of sampling, and select a more suitable range of cascade density by designing fewer impellers.