Bepaling van gemiddelde en spreiding van de snelheidsverdeling met de kruiscorrelatiemethode

De laatste tijd wordt er veel onderzoek gedaan aan cohesief sediment. Het speelt een belangrijke rol bij het ondieper worden van havens en waterwegen, en bij andere soortgelijke problemen. Om cohesief sedimenttransport te kunnen voorspellen zijn gegevens nodig over de verdelingen van de groottes en de bezinksnelheden. Er bestaan veel methoden om...

Segmentation of silt particles from exposure with background by use of second derivative

Recently a lot of research is being done on cohesive sediment. It plays a major role in the shoaling of harbours and waterways, and in some serious environmental problems. To predict cohesive sediment transport, information is needed about the distributions of size and settling velocities. Many methods exist to determine sizes of suspended...

Determining particle size distributions from video images by use of image processing

Recently a lot of research is being done on cohesive sediment. It plays a major role in the shoaling of harbours and waterways, and in some serious environmental problems. To predict cohesive sediment transport, information is needed about the distributions of size and settling velocities. Many methods exist to determine sizes suspended...

An improved settling tube system for sand

General design aspects of settling tube systems for fall velocity analysis of sand are reviewed, with emphasize being placed on detection methods for particle arrival at the lower end of the settling column and the various sources of errors. This is followed by a detailed discussion on the development of an improved settling tube system...

Terminal velocity formula for spheres in a viscous fluid

Various attempts have been made to develop a general expression for the terminal velocity of spheres in a viscous fluid (Stokes, Prandtl, Oseen, Rubey, etc.: see Bogardi, 1974 and Vanoni, 1975). All of these formulae show a lack of accuracy and/or are restrict ed to a relatively small range of Reynolds numbers. Since sieving is a time consuming...

An improved settling tube system

In this report a settling tube system is described for the measurement of the settling velocity distribution of sand samples with particle diameters ranging from 0.1 to 2 mm and sample weights ranging from 0.1 to 20 gf(10^-3 to 0.2 N). The time of arrival of the particles is detected by means of an underwater balance. The response, stability and...

Optische Sedimentconcentratiemeter

Voor het bestuderen van sedimenttransport onder invloed van golven en stroming is meetapparatuur noodzakelijk waarmee de sedimentconcentratiemomentaan gemeten kan worden. De te meten concentraties zullen uoorgaans liggen tussen 100 en 10000 ppm. Het nauwkeurig meten van ue lage concentraties zal i.h.a. een probleem vormen i.v.m. de stabiliteit...

Settling Tube Analysis of Sand

For various reasons particle-size analysis of sediment is used in many fields of science and technology, a.o. earth sciences, agricultural and civil engineering. Relatively coarse-grained sediment like sand, with dimensions ranging from 0.06 till 2 mm, is analyzed almost exclusively by sieving. The size of particles in the silt and clay range (0...

Design aspects and performance of a settling tube system

The DUST (Delft University Settling Tube) is a settling tube system intended to analyse particle size (settling velocity) of sand ranging from 0.06 mm to 2 mm, with the sample mass varying from 0.5 g to 20 g. The main parts of the system are (see fig. 1): a. the sample introduction device (venetian blind with rotating lamellae) b. the settling...

Valkolom: Intern voortgangsrapport

De valkolom, geconstrueerd door de Centrale Werkplaats, naar aanleiding van een onderzoek door Rietdijk, is bedoeld voor de analyse van zandmonsters. Met de valkolom kan men de valsnelheidsverdeling van zandmonsters bepalen, waaruit, desgewenst, een korrelgrootteverdeling afgeleid kan worden. Een andere manier om de korrelgrootteverdeling te...