Spectral energy of high-speed over-expanded nozzle flows at different pressure ratios

The purpose of this dataset is to provide a complete and reproducible record of a study on low-frequency unsteadiness in the interaction between a shock wave and a turbulent boundary layer (SBLI) in transonic flow within an convergent–divergent nozzle (pressure ratios PR = 1.44, 1.6, 1.81).The numerical dataset includes:the full definition of the computational domain (geometry.dsco),the computational mesh (mesh.msh),the applied physical models, solver settings, and initial and boundary conditions used in the simulations (in*.cas.h5 input files),time-series data enabling reproduction of the spectral analysis of static pressure signals (static_pressure.txt),flow-field data for the longitudinal section of the nozzle, used to determine the instantaneous shock-wave position and to perform spectral analysis of its motion (.plt files located in the field_output directories),processed results, including FFT spectra and other statistical quantities (static_pressure.lpk, shockwave_x_position.lpk, and shockwave_x_position.csv).The experimental dataset includes:DATA_AVI (video data) – recordings for selected operating conditions (pressure ratios PR = 1.44, 1.6, 1.8), including time and frame number information,DATA_pressure, containing:time of measurement [s],high-frequency static pressure signals: P1AC, P2AC, P3AC [kPa],FFT results for the high-frequency pressure signals (frequency and amplitude components),time-averaged static pressure distribution at multiple locations in the nozzle (P1–P32),inlet conditions, including pressure, temperature, and humidity,Static pressure signals, FFT spectra and time-averaged static pressure distributions can be found in separate .png files.The .dsco file is a native format of ANSYS Discovery, in which it was originally created. The .msh file is generated by the meshing tool within the ANSYS environment and is also a native format. Similarly, .cas.h5 files are input files used by ANSYS Fluent.The .plt files contain simulation results exported directly from ANSYS Fluent and can be opened using Tecplot. The .lpk files are project files created in Tecplot and are native to this software.We acknowledge that these file formats are not fully accessible using free or open-source software. At present, we are not aware of fully compatible open-format alternatives for all included data types. Where feasible, future updates of the dataset may include additional exports in more accessible formats.The dataset enables full reproduction of the numerical and experimental results presented in the associated publication, including analyses of shock-wave motion, variations in oscillation amplitude, and the decomposition of the signal spectrum into characteristic frequency bands. The data provide a basis for further investigation of the mechanisms governing global flow unsteadiness and for evaluating the applicability of the URANS approach in modeling SBLI phenomena.