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Sediment Transport in the Coastal Sea
Published in Paul Cadelina Rivera, Hydrodynamics, sediment transport and light extinction off Cape Bolinao, Philippines, 2020
The particle velocity is derived from a balance of forces acting on a particle which include gravity, drag and frictional forces. ub is approximated by ub=u∗[9+2.6log(D∗)−8(θcrθ)12]
Optimizing Thermoacoustic Characterization Experiments for Identifiability Improves Both Parameter Estimation Accuracy and Closed-Loop Controller Robustness Guarantees
Published in Combustion Science and Technology, 2022
Xiaoling Chen, Jacqueline O’Connor, Hosam Fathy
The input to the thermoacoustic system is the acoustic particle velocity from the speaker at the inlet and the output is the local pressure oscillation along the tube. The input particle velocity can be estimated using the two-microphone method (TMM) (Bodén and Åbom 1986). Because the input and output variables have different units, we normalize them before calculating the system transfer function. The nominal particle velocity and pressure oscillation used for normalization are bulk flow velocity, , and atmospheric pressure, . The definitions of the normalized transfer function, input, and output are in Eqn. (6).
Numerical study on particle-carrying ability of liquid nitrogen jet
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Shikun Zhang, Fanghui Liu, Zhongwei Huang, Jianxiang Chen
Figure 12 shows the particle velocities along nozzle axis with different nozzle pressure drops. With the rise of pressure drop, the particle velocity increases significantly. For instance, the maximum particle velocity is only 125.1 m/s with 10 MPa pressure drop, while it reaches 287.3 m/s when pressure drop is 50 MPa, increasing by 127.7%. However, with pressure drop lifting, the increment of particle velocity reduces gradually. It also can be noticed from Figure 12 that there are some fluctuations of velocity curve under 10 MPa pressure drop condition. That is because the potential core length is limited in that condition. The turbulence flow enhances after potential core disappearing, causing the fluctuation of particle velocity.
A direct-reading particle sizer with elemental composition analysis for large inhalable particles
Published in Aerosol Science and Technology, 2022
James Sipich, Christian L'Orange, Kimberly Anderson, Christopher Limbach, John Volckens, Azer Yalin
This work builds upon the portable inhalable particle separator (Anderson et al. 2015) to perform particle sizing based on a particle’s terminal settling velocity (VTS), the constant velocity achieved when drag and gravitational forces are in equilibrium (Hinds 1999). The determination of terminal settling velocity allows for the calculation of aerodynamic diameter (da): where ρ0 is the standard particle density (1000 kg/m3), g is the acceleration due to gravity, Cc is the slip correction factor (Cc = 1 for particles >20 µm), η and ρg are the dynamic viscosity and density of the surrounding gas, respectively. The aerodynamic diameter is the diameter of a spherical particle of standard density with equal settling velocity as the particle in question; and defines the aerodynamic properties of the particle necessary for characterizing filtration and respiratory deposition. The relationship between settling velocity and aerodynamic diameter (Equation (1); Hinds 1999) takes on a different functional form depending on the particle Reynolds number (Re). In the Stokes regime (Re < 1), there is a theoretical basis for the relationship between particle velocity and particle size based on the Navier-Stokes equation. However, at Reynolds numbers greater than 1, the assumptions made in the Stokes regime are no longer valid, and an empirical solution based on experimentation is used in the transition region (1 ≤ Re ≤ 1000). The transition from Stokes to transition flow typically occurs for particle settling at aerodynamic diameters of ∼80 µm and larger.