Bio-inspired forward and backward swimming gaits resulting from fluid-structure interactions

Biological undulatory swimmers display a wide range of gaits and are adept at swimming in different directions. This study explores the impact of passive dynamics as a result of fluid-structure interaction on the gaits of a model swimmer through computational simulations. Inspired by slender-bodied natural aquatic swimmers, the model consists of a flexible body and a rigid head. Systematically varying body stiffness and head pitching, the research replicates various swimming patterns observed in nature (both forward and backward). Optimal forward gaits, akin to anguilliforms and carangiforms, result from low to high bending rigidity and small pitching amplitudes. Conversely, low bending rigidity with high pitching amplitude produces backward swimming (tail-first), similar to mosquito larvae, exhibiting unique flow-field features and generating backward propulsion forces. The study underscores the significant role of passive dynamics in undulatory swimming and the potential for diverse g..., Data is collected by simulation using an in-house fluid-structure interaction solver. The raw data from the simulations are further processed using MATLAB. All the details about the script file are mentioned in the respective folders., , # Bio-inspired forward and backward swimming gaits resulting from fluid-structure interactions

[https://doi.org/10.5061/dryad.cz8w9gj9q](https://doi.org/10.5061/dryad.cz8w9gj9q)

## Description of the data and file structure

There are four different folders: Solver_source_code, Post_processing_code, Data and Movies.

### 1. Solver\_source\_code:

This folder contains in-house FSI solver code which is used to generate the data in this study. The source code is written in C++ language, and it is also parallelized using OpenACC to run the simulation on GPU. To compile and run the simulation, please follow the following steps:

\-->// First load the GPU module using the following command in the terminal (it should be changed as per the nvhpc version)//

module load nvhpc/20.7

\-->// Compile the souce_code using the following command in the terminal (Note that one should change the cc80 to the specific GPU used, and it can checked by typing pgaccelinfo in a terminal window) //

pgc+...