Experimental Database

This is a dataset for the 25% scale DrivAer model. Data was collected in the Large Wind Tunnel at Loughborough University, a 2.5m^2, closed working section, fixed ground open return tunnel.

The CAD geometry for the mounting hardware and the wind tunnel are all included in the dataset as ASCII .stl files, with the units in m. The CAD geometry of the DrivAer model has not been duplicated for this dataset.

Photos of the set up and some unique model dimensions are also included. The model was supplied by FKFS and is a 25% scale DrivAer model with three backs, the estate, fast and notchback variants. The model included the 5 spoke wheels, complex underbody, wing mirrors, the drivetrain, an open front grill and a porous radiator. As the model is not symmetric, in the engine bay and on the underside, it was set at a geometric 0 yaw condition as measured in the wind tunnel. This is estimated to be +/-0.1 degrees.

No corrections (for example blockage) have been applied to the data. All the data is presented in SI units and all measurements are from the origin (mid-track, mid-wheelbase on the tunnel floor) with x positive downstream and z positive up, using the right hand rule to find positive y.

The data is split into '_Mean' and '_Instantaneous' for each measurement type (Force, Pressure, Flow Field). All the data was taken during the same test session with a total sample time of 300 seconds typically and 100 seconds for the measurements in the stagnation region. The different data sets are not correlated with each other in time. The Force data was sampled at 300Hz, Pressure data at 260Hz and the Flow Field data at 5Hz. The data presented in the '_Mean' folders is the arithmetic mean of that presented in the '_Instantaneous' folders.

All the '_Mean' folders contain Comma Separated Variable (csv) files, for ease of parsing with your desired programming language, and the same data is provided in a .dat file that is set up to be read into TecPlot. The csv format was used to reduce size and complexity for the '_Instantaneous' data. Example MATLAB code has been provided (tested in 2018a) that reads both the '_Mean' and '_Instantaneous' csv files for the pressure and flow field measurements, plotting them accordingly.

Data object contains model geometry, aerodynamic loads, and velocity field measurements of the trailing vortex from PIV.

An experimental investigation has been performed to measure the inflow of a two-bladed propeller. This is conducted over a range of advance ratios (J =0.36 to 1.54) and yaw angles (γ = 0 to 20◦) at a Reynolds number of Re ≈ 111000, based on the chord length and advancing blade resultant velocity at the 70% spanwise position. Drawing on experimental results, three major qualitative trends are observed, that characterise the axial induced inflow of inclined propellers: the formation of an approximately sinusoidal inflow trend around the azimuth featuring broad regions of increased and reduced inflow, an azimuthal phase shift of the trend from the advancing and retreating blade positions, and the dependencies of the inflow maxima, minima and phase shift on advance ratio, yaw angle and radial position. These are subsequently compared against two widely used assumptions for calculating the aerodynamic environment of inclined propellers; firstly, that inflow at each radial and azimuthal element is calculated using an axial approximation of the whole propeller disc operating within the same condition as that element, and secondly, uniform induced inflow across the entire propeller plane. The comparison demonstrates the limitations of said assumptions by highlighting their inability to account for components of the trailed and shed vortical systems of the propeller wake.

Experimental data on the effect of steady and pulsed air jet vortex generator blowing on a RAE9645 aerofoil section in dynamic stall.

This dataset contains the measurements on the Axisymmetric body (160mm diameter, elliptical nose cone, l/d = 5), collated for Loughborough University by Max Varney on 2020/06/15. More information about this dataset can be found in the paper "Three-dimensional structure of the unsteady wake of an axisymmetric body", Physics of Fluids 31, 025113 (2019); https://doi.org/10.1063/1.5078379.

This Dataset is obtained from the Large Wind Tunnel at Loughborough University, which is a closed working section, fixed ground open return tunnel. The CAD geometry for the wind tunnel is included in the dataset as an ASCII .stl file, with the units in mm. The .stl file of the geometry and its mounting hardware is also provided, however, the yaw and pitch of the model were incrementally adjusted to produce an axisymmetric base pressure at each PIV plane and pressure measurement. As such the .stl file, as imported, will result in an asymmetric flow field.

For the purpose of ease of comparison with computational work, no corrections have been applied to this data. All data is presented in SI units and all measurements are from the origin of the model (on the base of the model, at the centre of the base) with x positive downstream and z positive up, using a right-hand rule to find positive y.

There are two datasets provided for this geometry.
DATASET #1 - 30m/s (Re_d=3.2x10^5)
Tomographic Particle Image Velocimetry
Base Pressures

Dataset #1 uses two sets of data appended to one another to generate a larger more statistically meaningful dataset. For the Tomographic Particle Image Velocimetry results, two experiments consisting of 250 uncorrelated vector fields (totalling 500 images) were used, taken at 7.26Hz. The base pressures use two sets of 90,000 samples (totalling 180,000 samples) taken at 300Hz (600 seconds total). There is no time correlation between the Tomographic and pressure results.

DATASET #2 - 40m/s (Re_d=4.3x10^5)
Planar (Y=0m, Z=0m and Z=0.04m) and Stereo (X=0.06m, X=0.12m, X=0.18m and X=0.24m) Particle Image Velocimetry
Base Pressures
Forces

Dataset #2 uses individual sets of data. Both the force and pressure measurements have 90,000 samples, taken at 300Hz (300 seconds total), these were taken at the same time (+/- 10 seconds) but are not correlated to one another. The vertical PIV at Y=0 m contains 1000 uncorrelated vector fields taken at 15Hz with all other planes containing 2000 uncorrelated vector fields.

For both datasets, a 300 second pressure measurement was taken to ensure the base pressure was close to axisymmetric prior to the Particle Image Velocimetry data being taken. The in-plane (planar) position of the Particle Image Velocimetry vectors are approximate, as they have been positioned manually.