Overview
| Lead Time | 12-16 Weeks |
|---|---|
| Temperature Range | 0 to 50ºC |
| Full System Consists of: | Sensor, Control Unit, 7-Pin LEMO Cable |
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DirectShear System
DirectShear® micromachined wall shear stress sensors deliver high-bandwidth (up to 20 kHz), high-resolution, and robust performance for subsonic and transonic flow applications.
- Principle of operation: The wall shear stress deflects a floating element, suspended by folded tethers, whose deflection is measured via differential capacitors to achieve a direct, time-resolved measurement.
- Flush-mountable design: Enables precise, hydraulically smooth skin friction measurements.
- Multiple sensor models: Various options available for different shear stress ranges and bandwidths.
- Package options: Select between a cylindrical or low-profile sensor package to meet your application needs.
- Calibration: Each sensor is paired and tuned with a companion control unit; calibration documentation included with purchase.
Originally developed for NASA, DirectShear sensors are ideal for precise skin friction measurements in wind tunnels. Click here to see how NASA is utilizing these sensors.
A complete DirectShear system includes sensor, cable, and control unit and operates as a paired set tuned together during the calibration process. Components can be ordered individually – however, each sensor requires a dedicated control unit.
Our team is here to assist with any questions – please reach out at sales@thinkic2.com, call us at 352-283-8110, or click here to schedule a Teams meeting.
From: $7,147
DirectShear sensors are micromachined, floating element devices that enable time-resolved, one-dimensional, direct mean and fluctuating wall shear stress measurements.
State-of-the-art wall shear stress measurement technology.
The micromachined silicon sensor and conditioning electronics provide the ability to simultaneously measure mean and fluctuating wall shear stress. A bundled system is also available to pair DirectShear sensors and PXI control units with NI PXI chassis and data acquisition hardware. IC2 designed full systems come with free software – which can be used as-is or modified to integrate into your larger data systems.
A complete DirectShear system includes the sensor, cable, and control unit. Components are available individually; each sensor requires a dedicated control unit.
- Direct, quantitative measurement of wall shear stress
- Non-intrusive, flush-mounted design minimizes flow disturbance
- Simultaneous mean and fluctuating shear stress data
- High resolution, wide dynamic range, and broad bandwidth
- Reliable, accurate results for demanding test scenarios
Datasheet
Product Flyer
User Manual
- Time-resolved, one-dimensional, direct wall shear stress measurements
- Compact, robust sensor package for flush mounting
- Suite of sensor models for different applications (see “Specifications”)
- Simultaneous mean and fluctuating measurements
- Multi-pin shielded sensor connector provides supply voltages and carrier signals
- Low-profile package available in a smaller form factor better suited to space-constrained testing scenarios
- Control units show system status and battery voltage LED indicators
- Standalone control unit offers integrated rechargeable lithium-ion battery system minimizes power line noise
- Modular PXI control unit available for expandable test setups
- Skin friction sensing for aerodynamic drag research
- Detection of flow separation in wind tunnels
- Turbulent boundary layer measurements
- Instrumentation-grade wall shear stress measurement in aerospace, automotive, wind energy, and research environments
Learn More About Related Applications ↓
Each sensor operates with a dedicated control unit.
- H2U Control Unit: Standalone, battery-powered, portable; larger footprint and higher cost.
- PXI Control Unit: Compact, modular, designed for integration with PXI chassis and data acquisition systems; ideal for multi-sensor setups and minimized installation space.
The following additional components and specifications are recommended for AC and DC testing/calibration with the capacitive sensor control unit:
- RG58 coaxial cable with BNC connectors
- Data acquisition system (DAQ) – AC/DC measurement
- Sensing Range: ±1, ±5, ±10V – sensor dependent (see datasheet)
- Resolution: 18+ bits
- Sampling frequency: sensor dependent – adequate sample rate and anti-alias filter to support sensor bandwidth
- Digital multimeter – DC measurement only
- 6.5 digits with power line cycle (PLC) integration
- DAQ or PC connection (e.g., GPIB)
Click here to learn more about the Complete Shear Stress Measurement System that leverages additional PXI hardware to create a full measurement solution.
| Model | Max Shear Stress (Pa) | Bandwidth (kHz) | Sensitivity (mV/Pa) | Resolution (mPa) | Element Size |
|---|---|---|---|---|---|
| 004x-A-00 | 50 | 1.5 | 40 | 0.1 | 2mm x 0.4mm |
| 004x-F-00 | 100 | 2.5 | 10 | 1 | 2mm x 0.4mm |
| 004x-B-00 | 300 | 5 | 1 | 1 | 1mm x 0.2mm |
| 004x-C-00 | 1000 | 10 | 0.3 | 5 | 0.5mm x 0.15mm |
| 004x-D-00 | 5000 | 20 | 0.08 | 10 | 0.5mm x 0.15mm |
Cylindrical package dimensions:
- Sensor Head Diameter: 12.7 mm (0.5″)
- Mounting Shoulder Length: 6.35 mm (0.25″)
- Sensor Body (Mounting Shoulder) Diameter: 15.9 mm (0.63″)
- Total Length: 50.8 mm (2″)
- Keyway for proper alignment with the flow direction.
Low-profile package dimensions:
- Sensor Head: 6 mm diameter, 9 mm length
- Sensor Base: 23 mm diameter, 4.3 mm length
- Total Length: 13.3 mm
Does each sensor need its own control unit? What is the difference between the Standalone and PXI control units?
Each sensor operates with a dedicated control unit. Standalone Control Unit: Standalone, battery-powered, portable; larger footprint and higher cost. PXI Control Unit: Compact, modular, designed for integration with PXI chassis and data acquisition systems; ideal for multi-sensor setups and minimized installation space.
Do DirectShear sensors work in liquids?
DirectShear sensors were developed and validated primarily for gaseous flow environments (e.g., air and wind tunnel testing). They are not currently rated or validated for continuous operation in liquids, including water. Use in liquid or multiphase flows is application‑dependent and must be evaluated on a case‑by‑case basis. The DirectShear‑Optical sensor may offer some advantages because there are no electronics in the sensing head, which can reduce certain failure modes. However: the optical sensor is also unvalidated in liquids, small gaps and cavities still exist where fluids may enter, and performance, long‑term stability, and biofouling behavior in liquids remain uncertain.
How cautious should I be when handling the sensor?
The sensing element (the front face) is fragile and any physical contact with the exposed sensing element can cause damage to the sensor. A protective cap is provided for handling purposes and should be used to keep the sensor face covered at all times when not in use. Proper sensor cleaning procedures are outlined in the provided User Manual.
How is the sensor typically mounted to the wall of a test section?
The sensor head may be placed in any known angular orientation with respect to the sensing axes. Angular misalignment during installation can result in increased uncertainty due to cross-axis sensitivity. Installation of the sensor head with the alignment key on the upstream side ensures alignment with the critical sensing axis. The sensor head should be inserted until the surface of the sensor head is flush with the facility wall. Proper design of the sensor installation port will provide repeatable installation depths and alignment via use of the shoulder and alignment key on the sensor head. Please contact IC2 for support with sensor installation.
How do acceleration forces affect the sensor?
DirectShear sensors withstand accelerations over 200g. However, acceleration can influence sensor output. For best results, use an accelerometer near the sensor and subtract coherent power during data analysis. Acceleration sensitivity data is included in the calibration packet.