Para acceder a los documentos con el texto completo, por favor, siga el siguiente enlace: http://hdl.handle.net/10256/8529

A noninvasive method for measuring the velocity of diffuse hydrothermal flow by tracking moving refractive index anomalies
Mittelstaedt, Eric; Davaille, Anne; Van Keken, Peter E.; Grácias, Nuno Ricardo Estrela; Escartín, Javier
Diffuse flow velocimetry (DFV) is introduced as a new, noninvasive, optical technique for measuring the velocity of diffuse hydrothermal flow. The technique uses images of a motionless, random medium (e.g.,rocks) obtained through the lens of a moving refraction index anomaly (e.g., a hot upwelling). The method works in two stages. First, the changes in apparent background deformation are calculated using particle image velocimetry (PIV). The deformation vectors are determined by a cross correlation of pixel intensities across consecutive images. Second, the 2-D velocity field is calculated by cross correlating the deformation vectors between consecutive PIV calculations. The accuracy of the method is tested with laboratory and numerical experiments of a laminar, axisymmetric plume in fluids with both constant and temperaturedependent viscosity. Results show that average RMS errors are ∼5%–7% and are most accurate in regions of pervasive apparent background deformation which is commonly encountered in regions of diffuse hydrothermal flow. The method is applied to a 25 s video sequence of diffuse flow from a small fracture captured during the Bathyluck’09 cruise to the Lucky Strike hydrothermal field (September 2009). The velocities of the ∼10°C–15°C effluent reach ∼5.5 cm/s, in strong agreement with previous measurements of diffuse flow. DFV is found to be most accurate for approximately 2‐D flows where background objects have a small spatial scale, such as sand or gravel
30-10-2013
Imatges -- Processament
Image processing
Fons marins
Ocean bottom
Tots els drets reservats
Artículo
info:eu-repo/semantics/publishedVersion
American Geophysical Union
         

Mostrar el registro completo del ítem

Documentos relacionados

Otros documentos del mismo autor/a

Mittelstaedt, Eric; Escartín, Javier; Olive, Jean-Arthur; Barreyre, Thibaut; Davaille, Anne; Cannat, Mathilde; García Campos, Rafael
Barreyre, Thibaut; Escartín, Javier; García Campos, Rafael; Cannat, Mathilde; Mittelstaedt, Eric; Prados Gutiérrez, Ricard
Escartín, Javier; García Campos, Rafael; Delaunoy, Olivier; Ferrer Vila, Jordi; Grácias, Nuno Ricardo Estrela; Elibol, Armagan; Cufí i Solé, Xavier; Neumann, László; Fornari, D.J.; Humphris, S.E.; Renard, J.
Prados Gutiérrez, Ricard; García Campos, Rafael; Grácias, Nuno Ricardo Estrela; Escartín, Javier; Neumann, László
Grácias, Nuno Ricardo Estrela; Negahdaripour, Shahriar; Neumann, László; Prados Gutiérrez, Ricard; García Campos, Rafael