Modares Mechanical Engineering

Modares Mechanical Engineering

Development and Evaluation a Model to Calculate the Skin Friction Coefficient and the Friction Drag Reduction of a Superhydrophobic Flat Plate

Document Type : Original Research

Authors
Mohammad Saadatbakhsh 1
Sadegh Sadeghzadeh 2
1 Kharazmi University
2 Iran University of Science and Technology
10.48311/MME.24.5.281
Abstract
Superhydrophobic surfaces have gained significant attention as a promising approach for drag reduction of submerged objects. Accurate evaluation and prediction of drag reduction induced by these surfaces require expensive experimental measurements, numerical simulations, or the development of reliable models and correlations. In this paper, a model is proposed for calculating the skin friction coefficient and drag reduction of superhydrophobic flat surfaces. Utilizing previous data on the skin friction coefficient of flat surfaces under no-slip boundary conditions, a model is developed to estimate the skin friction reduction and skin friction coefficient of these surfaces after applying superhydrophobic coatings. The validity of the model is verified by comparing its results with those of computational fluid dynamics (CFD) simulations of flow over a flat plate at different velocities. The results of the model and simulations indicate that for inlet velocities of 1, 5, and 25 m/s and a slip length of 50 μm, drag reductions of 15%, 41%, and 77%, respectively, are expected. Additionally, the skin friction reduction increases with increasing flow Reynolds number. The developed model is validated for flat surfaces and its ability to accurately estimate the skin friction coefficient and drag force of these surfaces is thoroughly examined. However, further investigations are required to assess the model's validity for curved surfaces and variable slip lengths.
Keywords
Flat plate
Drag Reduction
Skin friction coefficient
Superhydrophobic
Slip length

Subjects

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Modares Mechanical Engineering
Volume 24, Issue 5
April 2024
Pages 281-291