Fluid Mechanics

The Fluid Flow Laboratories consist of three divisions: the Water Flow, Gas Flow and Air Speed Laboratories. The services provided by the laboratories and work areas can be summarized as follows:


The TÜBİTAK UME Water Flow Laboratory has been built to cover the full range of industrial needs for water flow rate measurements in Turkey.

The capacity of the measurement lines and primary reference systems allows coverage of a flow rate range from 0.01 m3/h to 2000 m3/h with an uncertainty of less than 0.06 % (k=2).

There is a 300 m3 soft water reservoir inside the laboratory. There are several stainless steel pumps with frequency converters to control flow rate. The maximum flow capacities of the pumps are in the range of 20 m3/h to 1000 m3/h. The pumps are constructed to feed the calibration lines either directly or through the constant pressure head tanks. The head tanks located at the top of the tower have capacities of 50, 15 and 5 m3. The height of the tower is 35 m from the laboratory floor level.

For temperature controlled measurements (e.g. for hot water meters), there are two water feeding pumps and tanks with water temperature controllers, operating independently from the water reservoir that supplies hot and cold water to the measuring line.

There are 17 test lines in the range of DN-250 to DN-5, which consist of stainless steel pipes, remote controlled valves, various reference flow meters (e.g. Coriolis, magnetic and ultra-sonic) and instruments to measure water temperature and pressure. At the TÜBİTAK UME Water Flow Laboratory gravimetric systems are used as the primary reference system. There are four of these systems that were designed and built in Turkey. Their maximum weight capacities are 10 kg, 1 ton, 5 tons and 30 tons. All are operated at flying start and stop mode.

All instruments in the Water Flow Laboratory are controlled by a PLC system and measurements are performed by computer. The following types of measurements can be performed in the laboratory:

  • Testing and calibration for water flow meters
  • Cold and hot water meter testing
  • Valves, armatures and pump tests


The Gas Flow Laboratory has several reference flow meters that cover the volumetric flow range from 1 ccm to 20 000 m3/h.  Tests and calibrations of various gas flow meter devices can be performed using air as the medium in the laboratory.

The primary reference of the TÜBİTAK UME Gas Flow Laboratory is the Bell-Prover device. This device is covers an atmospheric air flow rate range of 0.2 m3/h to 85 m3/h with an uncertainty of 0.05 %. The Bell-Prover is traceable to the TÜBİTAK UME Dimensional, Pressure, Time-Frequency and Temperature laboratories. All reference standards in the Gas Flow laboratory are calibrated by the Bell Prover.

For low gas flow rates, there are wet gas meters and dry piton meters used as reference devices. Wet gas meters covers a flow rate range of 2 l/h to 18 000 l/h with 0.2% uncertainty and dry piston meters are used in the  1 ccm to 50 LPM range with 0.2% uncertainty.

Within the TÜBİTAK UME Gas Flow Laboratory, new measurement devices have also been developed. A sonic nozzle bank is the newest development. The sonic nozzle bank can provide a continuous flow rate up to 120 m3/h with an uncertainty of 0.25%. The whole system can be controlled by a computer. TÜBİTAK UME has the capability to develop such systems according to customer specifications and needs, especially for natural gas distribution companies and gas meter manufacturers.

There are also several reference turbine meters of different sizes for various flow rate ranges of air flow at atmospheric pressure. With those reference turbine meters and the pipe test rigs, the TÜBİTK UME Gas Flow Laboratory provides calibration and testing services for the following ranges;

  • 10 m3/h - 6600 m3/h with an uncertainty range of 0.11% to 0.43% depending on the flowrate
  • Up to 19500 m3/h the uncertainty is between 0.45% and 0.78% depending on the flowrate.


At present, the TÜBİTAK UME Air Speed Laboratory provides test and calibration services for various anemometers and air speed measuring devices within the speed range of 0.5 m/s to 40 m/s with a 250 mm square duct channel.

Two dimensional laser doppler anemometry (LDA) is used as the main reference measurement system in the air speed laboratory. To be able to make the LDA a primary reference system, a spinning disk device was designed and developed. The spinning disk device is simply a turning wheel at constant known speeds. Calibration of the LDA is performed by measuring the speed at outer surface of the wheel. Since the surface speed of the wheel is defined by angular speed and wheel diameter, the LDA system becomes traceable against the TÜBİTAK UME Dimensional and Time-Frequency Laboratories.

In the Air Speed Laboratory, for most of the calibrations and tests the pitot tube device is used as a reference.

A new wind tunnel which was designed by our laboratory staff and produced by a local company has been available for calibration and testing of air speed anemometers since February 2013. With the new tunnel, we have been able provide more stable speeds at much lower uncertainties.