Long-time-scale transients in an industrial-scale slurry pipeline near the laminar–turbulent transition

We revisit the laminar–turbulent transition of a fine-grained slurry in a large pipe. The combination of long measurement times in an industrial-scale facility and ultrasound imaging allows us to observe and address anomalous trends. Under turbulent conditions, the flow is homogeneous and steady. However, under laminar conditions, two types of...

Numerical investigation of turbulence in abdominal aortic aneurysms

Computational fluid dynamics (CFD) is a powerful method to investigate aneurysms. The primary focus of most investigations has been to compute various hemodynamic parameters to assess the risk posed by an aneurysm. Despite the occurrence of transitional flow in aneurysms, turbulence has not received much attention. In this article, we...

Instantaneous velocity field measurement in densely-laden two-phase flows using Ultrasound Imaging Velocimetry

Ultrasound Imaging Velocimetry (UIV, also known as 'echo-PIV') has, since its introduction a decade ago, been regarded as a promising tool to characterize non-transparent flows. Prime application examples are particle-laden flows and (in vivo) blood flow. Virtually all studies so far have been validation/comparison studies in laminar flow. In...

Tracking of vortices in a turbulent boundary layer

An experimental study of transitional pulsatile pipe flow

The transitional regime of a sinusoidal pulsatile flow in a straight, rigid pipe is investigated using particle image velocimetry. The main aim is to investigate how the critical Reynolds number is affected by different pulsatile conditions, expressed as the Womersley number and the oscillatory Reynolds number. The transition occurs in the...