Mach 5 Quiet Ludwieg Tube
QLT5 was installed in May 2019 and recently completed shakedown and calibration. Tunnel performance and calibration data are published in Bearden et al., 2022.
It currently operates as a conventional tunnel and a quiet nozzle upgrade is currently in the fabrication stage and is expected to be delivered in mid-2023. Tunnel run parameters and instrumentation are given in the tables below.
Tunnel operating parameters
| Parameter | Units | Range |
|---|---|---|
| Mach number | -/- | 5.0 |
| Quasi-steady run time | ms | 100 |
| Test-section diameter | mm (in.) | 381.0 (15.0) |
| Unit Reynolds number, Re' | 106 m-1 (106 ft-1) | 5.2–39.9 (1.6–12.2) |
| Total pressure, p01 | kPa (psia) | 344.7–2068.4 (50–300) |
| Total temperature, T01 | K (°F) | 385–450 (233–350) |
Tunnel Instrumentation
| Component | Channels | Specifications |
|---|---|---|
| NI PXIe-6378 analog-to-digital converters | 32 | 16-bit, 3.57 MS/s/ch. |
| NI PXIe-6361 analog-to-digital converter | 16 | 16-bit, 2 MS/s |
| NI PXIe-4353 thermocouple blocks | 64 | 24-bit, 90 S/s |
| Precision Filters 28144 resonant sensor excitation | 32 | ≥1 MHz bandwidth |
| Precision Filters 28612 programmable LP filter/amplifiers | 32 | fc ≤ 3 MHz |
| Kulite KSC-2 signal conditioner | 4 | Resonance compensation |
| FLIR X8501sc MWIR thermography | 2 | 14-bit, 1280×1024 px, 3.0 µm– 5.0 µm |
| Focusing schlieren (Photron FastCam SA-Z, Spectabit Optics) | 1 | up to 1024×1024 px, up to 2.1M fps (reduced res) |