Constant Temperature Anemometry (CTA)

Image of Constant Temperature Anemometry (CTA) test setup

Constant Temperature Anemometry (CTA), also known as Thermal Anemometry, Hot-wire, or Hot-film Anemometry is a technique for the measurement of turbulence in 1D, 2D, or 3D gas and liquid flows using hot-wire or hot-film probes inserted into the flow.

CTA is particularly suitable for the measurement of flows with very fast fluctuations at a point (high turbulence) and the study of flow microstructures, where there is a need to resolve small flow eddies down to the order of tenths of a millimeter.

CTA Solutions

 

StreamLine Pro

The StreamLine Pro system is the research grade anemometer solution for advanced flow and turbulence diagnostics
 

Multichannel CTA

The Multichannel CTA offers an efficient and affordable solution for mapping of velocity and turbulence fields in most air flows
 

MiniCTA

The MiniCTA system is a versatile anemometer that can be used with Dantec Dynamics standard wire and film probes
 

Standalone Calibrator

The CTA Standalone Calibration solution offers automated high accuracy velocity calibration of any hot-wire or hot-film sensor.

Features & Benefits

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Application Notes

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Measurement of wall shear stress with a 55R45 sensor

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Wind Conditions Along An Aircraft’s Flight Path

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Download Library

TITLE
AUTHOR(S)
YEAR
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AUTHOR(S)

F. G. Ergin a), F. Zafiryadis b), and B. B. Watz a) and K. E. Meyer c)

YEAR

2023

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AUTHOR(S)

F. G. Ergin 1, F. Zafiryadis 2, and B. B. Watz 1 and K. E. Meyer 3

YEAR

2023

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AUTHOR(S)

F. Gökhan Ergin1, Carsten Pedersen2, Francisco Felis1

YEAR

2019

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AUTHOR(S)

Frederik Zafiryadis, Knud Erik Meyer, F. Gökhan Ergin

YEAR

2017

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AUTHOR(S)

V. Jaunet, J. F. Debiève and P. Dupont

YEAR

2012

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AUTHOR(S)

F. Gökhan Ergin, Dantec Dynamics A/S

YEAR

2007

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AUTHOR(S)

F. Gökhan Ergin, Edward B. White

YEAR

2006

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AUTHOR(S)

F. Gökhan Ergin, Edward B. White

YEAR

2005

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AUTHOR(S)

F. Gökhan Ergin, Meelan Choudhari, Paul Fischer, Anatoli Tumin

YEAR

2005

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YEAR
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AUTHOR(S)

Finn E. Jørgensen

YEAR

2005

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FAQ

Q) LDA vs. CTA: pros and cons

For turbulence and flow measurements, LDA (Laser Doppler Anemometry) and CTA (Constant Temperature Anemometry / hot-wire) are complementary techniques rather than direct replacements.

Quick Comparison

AspectLDACTA (Hot-wire)
Measurement principleOptical, Doppler shift of seeded particlesThermal cooling of heated wire
Intrusive?Non-intrusiveIntrusive
Spatial resolutionGood, measurement volume ~0.1-1 mmExcellent, wire length often <1 mm
Temporal resolutionGood (kHz range)Excellent, up to hundreds of kHz
Near-wall measurementsDifficultExcellent
Calibration requiredNo direct velocity calibrationRequires calibration
Flow seedingRequiredNot required
Reverse flow detectionExcellentDifficult
Multi-component velocityEasy (1D, 2D, 3D systems)More complex
Access through optical windowRequiredNot required
CostHighLower
Installation complexityHighModerate

Choose LDA if your priority is:

Non-intrusive measurements

  • Accurate mean velocities
  • Reverse-flow detection
  • Combustion or harsh environments
  • 2D/3D velocity measurements

Choose CTA if your priority is:

Turbulence research

  • High-frequency fluctuations
  • Near-wall measurements
  • Turbulence spectra
  • Budget-conscious laboratory work

Practical recommendation

For mean flow mapping, validation of CFD, wakes, jets, and industrial flow diagnostics: choose fiber-optic LDA.

For fundamental turbulence research, especially when studying energy spectra, dissipation, or boundary-layer physics, CTA is often still the preferred tool because of its exceptional temporal and spatial resolution.

A common approach in advanced fluid mechanics labs is to use both:

  • LDA for accurate, non-intrusive velocity fields.
  • CTA for high-resolution turbulence characterization.

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