“Fluid Dynamics Unleashed: Exploring Nature-Inspired Swimming Techniques Through Biointegration”

Details of the data and file organization

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

1. Solver_source_code:

This folder includes proprietary FSI solver code utilized to produce the data in this study. The source code is developed in C++ language and is also parallelized using OpenACC to execute the simulation on GPU. To compile and execute the simulation, please adhere to the following steps:

–>// Initially, load the GPU module using the provided command in the terminal (it should be adapted as per the nvhpc version)//

module load nvhpc/20.7

–>// Compile the source_code using the subsequent command in the terminal (Note that one should modify cc80 to the specific GPU utilized, and it can be confirmed by typing pgaccelinfo in a terminal window) //

pgc++ -o make.out -acc -Minfo=accel -ta=tesla:cc80 source_code.cpp

–> To run the simulation, input the following command in the terminal

./make.out > output.txt

–>// Alternatively, one may also submit the job for simulation using run_IBMFSI.cmd (this script file is provided in the corresponding folder) //

qsub run_IBMFSI.cmd

2. Post_processing_code:

This folder contains all the MATLAB scripts for the postprocessing (i.e., generating figures). This code can be executed within MATLAB, and all the necessary details are provided within the code and directory.

3. Data:

This folder includes all essential data for the MATLAB plotting utilizing the Post_processing_code in the present study. This directory should be copied into the appropriate path during MATLAB code execution.

The ‘Data’ folder comprises the following five subfolders:

a. gamma_0_015 –> (Theta_10, Theta_60)

b. gamma_01 –> (Theta_30)

c. gamma_03 –> (Theta_10, Theta_25)

d. gamma_05 –> (Theta_25)

e. gamma_07 –> (Theta_10, Theta_60)

Here, gamma signifies bending stiffness, and the suffix represents the values of bending stiffness. For instance, gamma_01 indicates that the value of gamma is 0.1 (gamma=0.1). Each of the gamma folders contains the Theta folders, where Theta denotes the pitching amplitude, and the suffix indicates the corresponding values. There are four .dat and one .txt files present in each of the ‘Theta’ folders named as Drag_inst.dat, Lift_inst.dat, xf_total.dat, yf_total.dat, forcec.txt.

a. Drag_inst.dat: This file contains instantaneous Drag coefficient data in .dat format. It comprises 271 columns listing instantaneous drag coefficients corresponding to each node of structural elements.

b. Lift_inst.dat: This file contains instantaneous Lift coefficient data in .dat format. It consists of 271 columns listing instantaneous Lift coefficients corresponding to each node of structural elements.

c. xf_total.dat: This file includes instantaneous structural displacement data in the x-direction in .dat format. It has 272 columns, where the first column represents the instantaneous non-dimensional time (non-dimensionalized using reference velocity and the body length of the numerical swimmer), while the remaining columns represent instantaneous structural displacements (normalized using the total body length of the numerical swimmer) corresponding to each node of structural elements.

d. yf_total.dat: This file contains instantaneous structural displacement data in the y-direction in .dat format. It also has 272 columns, where the first column indicates the instantaneous non-dimensional time (non-dimensionalized using reference velocity and the body length of the numerical swimmer), and the remaining columns reflect instantaneous structural displacements (normalized using the total body length of the numerical swimmer) corresponding to each node of structural elements.

Note that xf_total.dat and yf_total.dat are used to analyze the mode shapes.

e. forcec.txt: This file contains the instantaneous total hydrodynamic force in .txt format acting on the entire body. It contains four columns, where the first column shows the instantaneous non-dimensional time (non-dimensionalized using reference velocity and the body length of the numerical swimmer), and the last three columns represent instantaneous total Drag coefficient, total Lift coefficient, and total moment coefficient, respectively.

4. Movies:

This folder includes additional Movies demonstrating vortex interactions for the current results.

Sharing/Access information

One can also access the folders containing source code and Matlab scripts as well as the vortex interaction movies using the following link:

Code/Software

In this study, the proprietary Immersed Boundary Method (IBM)-based Fluid-structure Interaction (FSI) solver is developed in a C++ environment, and all postprocessing is performed in MATLAB.