DOI: 10.5061/dryad.1g1jwsv25
title: Data from: Energy harvesting in a flow-induced vibrating flapper with biomimetic gaits

description: Energy harvesting from flow induced vibrations (FIV) in flexible bodies
 offer opportunities for power generation in biomimicking robotic
 devices and is an active area of research. The focus of this
 study is on investigating the underlying physics
 and qualitatively analysing the energy extraction scenarios in
 similar structural systems, comprising of a flexible
 piezoelectric flapper in a low Reynolds number flow regime.
 A high-fidelity three-way fully coupled fluid-structure-electric
 energy solver is developed in-house to study the energy
 harvesting capabilities of such a flapper, its
 hydrodynamic characteristics and the associated unsteady
 flow-field. The results indicate that the flapper deformation
 profiles at the most efficient harvesting regimes, resemble
 the propulsion gaits of natural swimmers. Investigations on the
 effects of a sinusoidal heaving actuation reveal no significant
 impact on the harvested power at the high yield (high power
 output) regime, identified under the passive condition showing
 biomimetic gait. This study provides mechanics based insights
 that is expected to be useful for bio-inspired designs of FIV
 based harvesters.
description: This dataset includes the codes used for the simulation in the
 manuscript, as well as the data generated from it. A range of flexibility
 and inertia parameters were used in the same code to generate the data
 listed in the .dat, .txt files. These datasets were used for
 post-processing by post-processing codes (also included here) to generate
 the .csv files. Details are provided in the corresponding readme.md
 file. These datasets (.csv,.dat) were used to generate
 the figures (.fig-&gt;.eps files) with the post processing codes. The
 saved .eps files are then post-processed by using inkscape to generate a
 combined figure in .eps format. The schematics are also drawn in
 inkscape. Details of the data usage guidelines are mentioned in the readme
 file.
description: The .dat, .txt files can be opened with any text reader (e.g.
 text editor) The .csv files can be opened with any
 excel file reader (Microsoft Excel/LibreOffice Calc)
 The .m codes can be opened and run by any version of Matlab
 (preferably &gt;2021a). The .cpp files can be
 opened by gedit and run with pgc compilers. (details provided in the
 readme file for the code)
description: # Energy harvesting in a flow-induced vibrating flapper with biomimetic
 gaits Flow induced vibrating flappers with biomimetic gaits are energy
 efficient This dataset contains all the raw data derived from the direct
 simulation for the range of parametric space. These datasets have been
 used for post-processing to get the derived datasets as well as to
 generate the figures. Description of the Data and file structure #
 Convergence studies *=11,51,101 $=01,004,002 \**=001,0001 These numbers
 denote the level of fineness of element, grid and time-step size used in
 the folder numbering. ``` cd IJMS_submission/IJMS submission/Data/ Data\\\
 folder/convergence_tests/element/n=* /mesh/grid=$ /time/t=** ```
 xf_total.dat: 1st column contains time stamps, 2-nd column contains X
 displacement location time history along the flapper arc length.
 yf_total.dat: 1st column contains time stamps, 2-nd column contains Y
 displacement location time history along the flapper arc length.
 Voltage.dat: Contains time history of non dimensional and dimensional
 voltage in column-2,4 respectively. (note that, the dimensional voltage
 depends on the chosen dimensional parameters.) # For passive configuration
 \[xx,yy]={[10^-2, 0.5], [10^-2, 1], [7.5*10^-3,2.5], [10^-3,1],
 [5*10^-4,0.1]} ``` cd IJMS_submission/IJMS submission/Data/ Data\\\
 folder/passive_cases/RegimeA:gamma=xx_beta=yy/ ``` Flow_field.dat :
 contains velocity data over the whole domain at the time instant where the
 flapper reaches its maxima. body_profile_for_flow_field.dat: contains body
 profile shape at same instant (X,Y locations).
 displacement_time_hist_X.dat: X displacement location time history along
 the flapper. displacement_time_hist_Y.dat: Y displacement location time
 history along the flapper . lift_for_Fv_cal.dat: lift time history varying
 over the flapper. drag_for_Fv_cal.dat: drag time history varying over the
 flapper. Cd_Cl_for_meanCd_Zeta_cal.txt: Total CD CL time history.
 Voltage.dat: Contains time history of non dimensional and dimensional
 voltage in column-2. (note that, the dimensional voltage(column-4) depends
 on the chosen dimensional parameters.) Data/Data
 folder/passive_cases/data_for_pn.xlsx: Contains the tip excursion (Am),
 frequency of oscillation (f), Strouhal numbers(St), power coefficient (Pn)
 for figures Fig.4 and Fig.7 along with beta and gamma values. Data/Data
 folder/passive_cases/data_for_angle_zeta.xlsx: Contains the RMS passive
 pitching angle (alpha_rms), , aero/hydrodynamic efficiency (zeta) for
 Fig.6 along with beta and gamma values. # For active configuration
 \[*,$]={
 [1,1],[1,2],1,4],[1,6],[1,10],[1,12],[1,16],[2,1],[2,2],[2,4],[2,6],[3,0.5],[3,1],[3,2],[3,4] ``` cd IJMS_submission/IJMS submission/Data/Data folder/active_cases/case*/kappa=$ ``` xf_total.dat : 1st column contains time stamps, 2-end column contains X displacement location time history along the flapper; For Fig.9,10,11. yf_total.dat : 1st column contains time stamps, 2-end column contains Y displacement location time history along the flapper; For Fig. 9,10,11. Voltage.dat : 1st column contains time stamps, 2nd column contains non dimensional Voltage time-history . For Fig. 9,10,11. Data/Data folder/active_cases/data_act_fin.xlsx: Pn_fact.m uses this data to plot Fig.~12. Sharing/access Information This data has not yet been used for any other publication ## Codes This codes folder contains all the codes used for direct simulation for the range of parametric space as well as the post-processing codes used for generating the derived datasets as well as to generate the figures. Description of the Data and file structure ——-File Description——- ``` cd IJMS_submission/IJMS submission/source_codes/ ``` main_source_code.cpp: source code for the three-way coupled fluid-structure-energy solver. # ——-How to run the source code:——- step 1: set desired gamma and beta values in main_source_code.cpp. step 2: load GPU module (nvidia hpc-sdk 20.7 was used) step 3: compile with ``` pgc++ -o a.out -acc -Minfo=accel -ta=tesla:cc80 main_source_code.cpp ``` step 4: set ulimit -s unlimited step 5: run with ./a.out # ——Post processing codes:——- The specified .dat files can be imported from available data folder in matrix format. The matlab (.m) codes generate the data and figures. displacement_time_hist_Y.dat. file provided in dataset. PSD_disp_frequency.m: code for power spectral density calculation from displacement time history data Deformation_env_Pn_cal.m: code for generating the Pn and St values. Saved in the data_for_Fig_2_4_5.xlsx Also generates the deformation envelopes for the particular case. Import displacement_time_hist_X.dat, displacement_time_hist_Y.dat in xf and yf variables for the envelopes. Pn_st_plot.m: code for post processing of data_for_2_5.xlsx. Generates Pn vs Am plot and Pn vs St plot. alpha_rms_Cd_zeta.m: code for getting rms values of passive pitching angle, mean Cd and zeta from displacement_time_hist_X.dat,displacement_time_hist_Y.dat, Cd_Cl_for_meanCd_Zeta_cal.txt and saved in data_for_angle_zeta.xlsx. plot_Fig4.m: code for post-processing of data_for_angle_zeta.xlsx.dat, to generate vs alpha_rms and zeta vs alpha_rms with second order polynomial curve fitting in Fig.6 Fv_new.m: code for calculating Fv from the temporally and spatially varying lift and drag loads in lift_for_Fv_cal.dat and drag_for_Fv_cal.dat, using displacement matrices: displacement_time_hist_X.dat, displacement_time_hist_Y.dat. Pn_fact.m: code for plotting Pn vs f_act in Fig. 12. strain_rate.m: Import xf_total.txt and yf_total.txt and run Deformation_env_Pn_cal.m for Fig. D.19.