Kiefer, Janik; Brunner, Claudia E.; Hansen, Martin O. L.; Hultmark, Marcus
This data set contains data of a NACA 0021 airfoil as it undergoes upward ramp-type pitching motions at high Reynolds numbers and low Mach numbers. The parametric study covers a wide range of chord Reynolds numbers, reduced frequencies and pitching geometries characterized by varying mean angle and angle amplitude. The data were acquired in the High Reynolds number Test Facility at Princeton University, which is a closed-loop wind tunnel that can be pressurized up to 23 MPa and allowed for variation of the chord Reynolds number over a range of 5.0 × 10^5 ≤ Re_c ≤ 5.5 × 10^6. Data were acquired using 32 pressure taps along the surface of the airfoil. The data are the phase-averaged results of 150 individual half-cycles for any given test case.
Brunner, Claudia E.; Kiefer, Janik; Hansen, Martin O. L.; Hultmark, Marcus
Reynolds number effects on the aerodynamics of the moderately thick NACA 0021 airfoil were experimentally studied by means of surface-pressure measurements. The use of a high-pressure wind tunnel allowed for variation of the chord Reynolds number over a range of 5.0 × 10^5 ≤ Re_c ≤ 7.9 × 10^6. The angle of attack was incrementally increased and decreased over a range of 0° ≤ alpha ≤ 40°, spanning both the attached and stalled regime at all Reynolds numbers. As such, attached and separated conditions, as well as the static stall and reattachment processes were studied. A fundamental change in the flow behaviour was observed around Re_c= 2.0 × 10^6. As the Reynolds number was increased beyond this value, the stall type gradually shifted from trailing-edge stall to leading-edge stall. The stall angle and the maximum lift coefficient increased with Reynolds number. Once the flow was separated, the separation point moved upstream and the suction peak decreased in magnitude with increasing Reynolds number. Two distinct types of hysteresis in reattachment were observed.
Abstract: Tokamak plasma facing components have surface roughness that can cause microscopic spatial variations in erosion and deposition and hence influence material migration, erosion lifetime, dust and tritium accumulation, and plasma contamination. However high spatial resolution measurements of deposition on the scale of the surface roughness have been lacking to date. We will present elemental images of graphite samples from NSTX-U and DIII-D DiMES experiments performed with a Scanning Auger Microprobe at sub-micron resolution that show strong microscopic variations in deposition and correlate this with 3D topographical maps of surface irregularities. The NSTX-U samples were boronized and exposed to deuterium plasmas and the DiMES samples had localized Al and W films and were exposed to dedicated helium plasmas. Topographical maps of the samples were performed with a 3D confocal optical microscope and compared to the elemental deposition pattern. The results revealed localized deposition concentrated in areas shadowed from the ion flux, incident in a direction calculated (for the DiMES case) by taking account of the magnetic pre-sheath.
Data set used to train a Deep Potential (DP) model for crystalline and disordered TiO2 phases. Training data contain atomic forces, potential energy, atomic coordinates and cell tensor. Energy and forces were evaluated with the density functional SCAN, as implemented in Quantum-ESPRESSO. Atomic configurations of crystalline systems were generated by random perturbation of atomic positions (0-0.3 A) and cell tensor (1-10%). Amorphous TiO2 was explored by DP molecular dynamics (DPMD) at temperatures in the range 300−2500 K and pressure in the range 0−81 GPa.
Data set used to train a Deep Potential (DP) model for
subcritical and supercritical water. Training data contain atomic forces,
potential energy, atomic coordinates and cell tensor. Energy and forces
were evaluated with the density functional SCAN. Atomic configurations
were extracted from DP molecular dynamics at P = 250 bar and
T = 553, 623, 663, 733 and 823 K. Input files used to train the DP model
are also provided.