Fast Response Measurement Systems

Unsteady probes combine the robustness of a pressure probe (e.g. 5-hole probe) with high temporal resolution pressure sensors.  Frequencies in the range of kHz are measurable, depending on the probe geometry.

Datasheet for unsteady measurement systems


Unsteady probes from Vectoflow make it possible to measure high-frequency flow phenomena in the kHz range and not just in terms of a single measured parameter.  All flow parameters normally measurable with a conventional multi-hole probe can be captured, such as velocities, flow angles, total and static pressure, Mach number and density.  In order to achieve this high temporal resolution, the pressure sensors are placed as close as possible to the probe head minimizing the attenuation and modulation of the pressure fluctuations in amplitude and phase.  The remaining modulation of the pressure signal is corrected by calibration at Vectoflow with a specially developed frequency calibration rig.  Of course, all of the advantages of the Vectoflow conventional probes are also available to the customers for the unsteady probes due to our proprietary additive manufacturing process.  The geometry of the probe can be fully customized and the one-piece construction of the probe head makes it very robust.

  • Complete measurement system for unsteady flow phenomena
  • Probes with embedded pressure sensors (high frequency response)
  • Conventional probes with high frequency response sensors attached outside of the probe are also available
  • Frequency calibration of each pressure channel
  • Hardware for data acquisition
  • Software for data post-processing


Geometry:  Straight, L-shaped, Cobra or Drilled Elbow; Pressure sensors per customer request (> 1 PSIG)

Number of pressure holesCustom (5-hole is standard)
Max. lengthCustom
Min. tip diameterStandard 3-4 mm (down to 1.0 mm with Micro-Printing techniques)
Shaft Diameter15 mm (standard)
Tip geometryConical, hemi-spherical or custom
MaterialStainless steel, titanium, inconel, plastics
Mounting methodSquare, hexagonal, one-sided flattened cylinder or custom
ReferenceReference surface normal to z-axis
Acquisition Hardware2x NI 9237; 1x cDAQ 9181 (Chassis); or custom
Acquisition & Postprocessing SoftwareIncluded (Labview based)
Temperature rangeup to 100°C (210°F) (higher with water cooling)
Angle range± 60° (depending on number of holes)
Angle accuracyless than ± 1°
Velocity range3 m/s (10 ft/s) up to Mach 1
Velocity accuracyless than ± 1 m/s (3 ft/s)

Frequency Calibration

Calibration SystemAcoustic Calibration
Frequency Rangeup to 25 kHz (dependent on probe geometry)
Transfer function frequency step sizeCustom