A test rig for the investigation of airflow through collapsible tubes

Oruç, Vedat; Çarpınlıoǧlu, Melda Özdinç

doi:10.1243/0954406jmes401

Cited by 5 publications

(5 citation statements)

References 21 publications

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“…Predictions of the linear stability theory are obtained via the experimental data acquired immediately at the onset of the oscillations. The experimental set-up is introduced in detail by Oruç and Çarpınlıoglu [11]. In the experimental work, longitudinal tension was not applied to the test tubes (σ = 0), T = σ /E s b; therefore T = 0.…”

Section: Methodsmentioning

confidence: 99%

“…In this case, the wall-damping coefficient R w is 0.5/s, which has been already cited in section 3. E w is calculated from equation (11) to be 6440 N/m 3 with b = 2.7 mm. Then the following parameters are calculated to be a = 0.49, c = 3.81 m/s, ω * = akS = 0.073, ω = 103.22 rad/s, f = 16.43 Hz, and u c = 2.97 m/s.…”

Section: Comparison Of Experiments With Theorymentioning

confidence: 99%

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Theoretical approximations to analyse the onset of self-excited oscillations in flow through collapsible tubes

Oruç

Çarpınlıoǧlu

2010

Proceedings of the Institution of Mechanical Engineers, Part C:

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In this study, flow through collapsible tubes is analysed theoretically for the case of the onset of collapse which induces self-excited oscillations. The basic tools in the theoretical calculations are the linear stability theory and the tube law. The experimental data in the form of measured oscillation frequency at the onset of collapse of an elastic tube is supplied as a base input parameter for the theoretical approximations. The calculations offer a possibility for estimating the unmeasured parameters such as critical oscillation speed, speed index, and tube cross-sectional area at the onset of collapse. It was seen by referring to the obtained results that theoretical predictions agreed with the experimental measurements.

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Section: Methodsmentioning

confidence: 99%

Section: Comparison Of Experiments With Theorymentioning

confidence: 99%

Theoretical approximations to analyse the onset of self-excited oscillations in flow through collapsible tubes

Oruç

Çarpınlıoǧlu

2010

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…2a. The latex tube (LXT) was inflated with an initial constant pressure (P 0 ¼800 Pa) before the experiment to avoid self-excited oscillations of the tube wall (Oruç and Çarpinliogľu, 2007). Pressure and velocity were sampled at 2 kHz.…”

Section: Single Vessel Experimentsmentioning

confidence: 99%

Wave intensity analysis in air-filled flexible vessels

Clavica

Parker

Khir

2015

Journal of Biomechanics

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Wave intensity analysis (WIA) is an analytical technique generally used to investigate the propagation of waves in the cardiovascular system. Despite its increasing usage in the cardiovascular system, to our knowledge WIA has never been applied to the respiratory system. Given the analogies between arteries and airways (i.e. fluid flow in flexible vessels), the aim of this work is to test the applicability of WIA with gas flow instead of liquid flow. The models employed in this study are similar to earlier studies used for arterial investigations. Simultaneous pressure (P) and velocity (U) measurements were initially made in a single tube and then in several flexible tubes connected in series. Wave speed was calculated using the foot-to-foot method (cf), which was used to separate analytically the measured P and U waveforms into their forward and backward components. Further, the data were used to calculate wave intensity, which was also separated into its forward and backward components. Although the measured wave speed was relatively high, the results showed that the onsets and the nature of reflections (compression/expansion) derived with WIA, corresponded well to those anticipated using the theory of waves in liquid-filled elastic tubes. On average the difference between the experimental and theoretical arrival time of reflection was 6.1% and 3.6% for the single vessel and multivessel experiment, respectively. The results suggest that WIA can provide relatively accurate information on reflections in air-filled flexible tubes, warranting further studies to explore the full potential of this technique in the respiratory system.

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“…1) which was mainly composed of a Starling resistor and connected piping system [10,11]. Airflow was generated by means of a screw type compressor in combination with a pressurized air tank.…”

Section: Experimental Set-up and Measurementsmentioning

confidence: 99%

An Approach for the Analysis of Collapse Onset in Elastic Tube Flows

Çarpınlıoǧlu

Oruç

2011

Arab J Sci Eng

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An experimental study conducted for the determination of the onset of collapse of an elastic tube of a Starling resistor conveying air is presented herein. The collapse was induced under the action of external pressure p e applied to the tube walls. The influence of length L , thickness h, and modulus of elasticity E of the tube on collapse were determined by using a variety of silicone rubber and latex-Penrose tubes. The experiments were conducted under the presence of constant upstream head with the absence of a longitudinal strain of the tube in a range of flow Reynolds number (Re) 16750 < Re < 70280. At each air flow rate Q through the tube, p e was increased gradually. The inlet and exit pressures of the tubes p 1 and p 2 were measured. The variation of Q with p e was used to determine the onset of collapse. The magnitude of p e at the onset of collapse was defined as p e,c . The visually observed collapse was associated with a flow rate reduction, followed by so-called oscillating and non-oscillating cases. The experimental data at the onset of collapse were expressed in terms of a correlation between Re (h/L) and a non-dimensional pressure parameter defined as ( p e,c − p 2 )/K p including circumferential bending stiffness of the tube K p .

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A test rig for the investigation of airflow through collapsible tubes

Cited by 5 publications

References 21 publications

Theoretical approximations to analyse the onset of self-excited oscillations in flow through collapsible tubes

Theoretical approximations to analyse the onset of self-excited oscillations in flow through collapsible tubes

Wave intensity analysis in air-filled flexible vessels

An Approach for the Analysis of Collapse Onset in Elastic Tube Flows

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