scispace - formally typeset
Search or ask a question
Author

Simone Ferrari

Bio: Simone Ferrari is an academic researcher from University of Sheffield. The author has contributed to research in topics: Vortex & Imaging phantom. The author has an hindex of 2, co-authored 4 publications receiving 11 citations.

Papers
More filters
Journal ArticleDOI
TL;DR: It is indicated that a liquid phantom based on the ring vortex may have merit as a complex flow phantom for multimodal imaging and availability of such a flow reference may also serve as a benchmark for quality assurance of simulation methodologies.
Abstract: Calibration of medical imaging systems that provide quantitative measures relating to complex physiological flows is challenging. Physical test objects available for the purpose either offer a known simple flow far removed from the complexity of pathology (e.g. parabolic flow in a straight pipe) or complex relevant flows in which the details of the flow behaviour are unknown. This paper presents the ring vortex as a candidate for a complex flow phantom, since it is marked by inherently complex flow features that are controllable, predictable, reproducible and stable. These characteristics are demonstrated by a combination of analytical, numerical (CFD) and experimental methods. Together they provide a consistent perspective on ring vortex behaviour and highlight qualities relevant to phantom design. Discussion of the results indicates that a liquid phantom based on the ring vortex may have merit as a complex flow phantom for multimodal imaging. Furthermore, availability of such a flow reference may also serve as a benchmark for quality assurance of simulation methodologies.

7 citations

Journal ArticleDOI
TL;DR: A novel, cost-effective, portable, complex flow phantom is proposed and the design specifications are provided, which employs a piston/cylinder system for vortex ring generation, coupled to an imaging tank full of fluid, for vortex propagation.
Abstract: Cardiovascular fluid dynamics exhibit complex flow patterns, such as recirculation and vortices. Quantitative analysis of these complexities supports diagnosis, leading to early prediction ...

4 citations

Book ChapterDOI
18 Oct 2017
TL;DR: The hypothesis of the present work is that the ring vortex combines characteristics of high complexity comparable to pathological flows but also offers characterizability comparable to simple flows, which deserves consideration as a candidate for a complex flow phantom.
Abstract: Flow informed diagnosis of cardiovascular diseases requires the accurate and specific interpretation of complex flow patterns acquired by medical imaging systems. Satisfactory imaging performance is assured through calibration and validation against known reference flows, but in the domain of complex flows these suffer from numerous limitations. The hypothesis of the present work is that the ring vortex combines characteristics of high complexity comparable to pathological flows but also offers characterizability comparable to simple flows. This is explored through a combination of experiment and theory involving ring vortex production in a water tank. Measurements confirm that despite the complexity of this vortical flow, it is stable, reproducible, predictable and controllable. The flow is sufficiently well behaved that it is consistent with some flow imaging standards, and consequently deserves consideration as a candidate for a complex flow phantom.

2 citations

Journal ArticleDOI
01 Aug 2021
TL;DR: This paper investigates a new real-time tool for simulating structural and fluid scenarios - ANSYS Discovery Live - and evaluates its capability in the fluid domain through benchmark flows that all involve steady state flow at the inlet and zero pressure at the outlet.
Abstract: Medical device design for personalised medicine requires sophisticated tools for optimisation of biomechanical and biofluidic devices. This paper investigates a new real-time tool for simulating structural and fluid scenarios - ANSYS Discovery Live - and we evaluate its capability in the fluid domain through benchmark flows that all involve steady state flow at the inlet and zero pressure at the outlet. Three scenarios are reported: i. Laminar flow in a straight pipe, ii. vortex shedding from the Karman Vortex, and iii. nozzle flows as characterised by an FDA benchmark geometry. The solver uses a Lattice Boltzmann method requiring a high performance GPU (nVidiaGTX1080, 8GB RAM). Results in each case were compared with the literature and demonstrated credible solutions, all delivered in near real-time: i. The straight pipe delivered parabolic flow after an appropriate entrance length (plug flow inlet conditions), ii. the Karman Vortex demonstrated appropriate vortex shedding as a function of Reynolds number, characterised by Strouhal number in both the free field and within a pipe, and ii the FDA benchmark geometry generated results consistent with the literature in terms of variation of velocity along the centreline and in the radial direction, although deviation from experimental validation was evident in the sudden expansion section of the geometry. This behaviour is similar to previous reported results from Navier-Stokes solvers. A cardiovascular stenosis example is also considered, to provide a more direct biomedical context. The current software framework imposes constraints on inlet/outlet boundary conditions, and only supports limited control of solver discretization without providing full field vector flow data outputs. Nonetheless, numerous benefits result from the interactive interface and almost-real-time solution, providing a tool that may help to accelerate the arrival of improved patient-specific medical devices.

Cited by
More filters
Journal ArticleDOI
TL;DR: In this article, the effect of variations in the ventilation rate on the distribution pattern of the 220Rn concentration in a thoron test house is used as input for the CFD simulations.

12 citations

01 Nov 2017
TL;DR: In this article, the evolution of vortex rings in isodensity and isoviscosity fluid has been studied analytically using a novel mathematical model, which predicts the spatiotemporal variation in peak vorticity, circulation, vortex size and spacing based on instantaneous vortex parameters.
Abstract: The evolution of vortex rings in isodensity and isoviscosity fluid has been studied analytically using a novel mathematical model. The model predicts the spatiotemporal variation in peak vorticity, circulation, vortex size and spacing based on instantaneous vortex parameters. This proposed model is quantitatively verified using experimental measurements. Experiments are conducted using high-speed particle image velocimetry (PIV) and laser induced fluorescence (LIF) techniques. Non-buoyant vortex rings are generated from a nozzle using a constant hydrostatic pressure tank. The vortex Reynolds number based on circulation is varied in the range 100–1500 to account for a large range of operating conditions. Experimental results show good agreement with theoretical predictions. However, it is observed that neither Saffman’s thin-core model nor the thick-core equations could correctly explain vortex evolution for all initial conditions. Therefore, a transitional theory is framed using force balance equations which seamlessly integrate short- and long-time asymptotic theories. It is found that the parameter , where is the vortex half-spacing and denotes the standard deviation of the Gaussian vorticity profile, governs the regime of vortex evolution. For higher values of , evolution follows short-time behaviour, while for , long-time behaviour is prominent. Using this theory, many reported anomalous observations have been explained.

6 citations

Journal ArticleDOI
TL;DR: The present study aims to simulate the effect of forced mixing on the 222Rn concentration profile in a 22 m3 experimental chamber, and Non uniformity index (NUI) is introduced as a measure of the uniformity of the distribution in the closed domain.

6 citations

Journal ArticleDOI
TL;DR: A novel, cost-effective, portable, complex flow phantom is proposed and the design specifications are provided, which employs a piston/cylinder system for vortex ring generation, coupled to an imaging tank full of fluid, for vortex propagation.
Abstract: Cardiovascular fluid dynamics exhibit complex flow patterns, such as recirculation and vortices. Quantitative analysis of these complexities supports diagnosis, leading to early prediction ...

4 citations

Journal ArticleDOI
TL;DR: In this paper, the authors used Computational Fluid Dynamics (CFD) code to simulate the behavior of aerosols and decay products of 222Rn/220Rn in indoor environments.
Abstract: In the present work, Computational Fluid Dynamics (CFD) code has been used to simulate the behaviour of aerosols and decay products of 222Rn/220Rn in indoor environments. The code has been incorporated with simulation modules describing relevant physical processes governing the aerosol and decay product dynamics such as particle deposition, gravitational settling, thermophoresis, coagulation and size dependent attachment of decay products to aerosol. Subsequently, reliability and consistency of the CFD code has been evaluated and validated by comparing simulated results with analytical and simulation results of well-known cases reported in literature. Comparison showed a good agreement within ± 3.5%.

3 citations