SV.DAT

Basic Information

File-Type

sv.dat

File-Form

FORMATTED

Version

1.x / July 2009

Description-Date

January 2018

Significance of the File

contains general input data for the program package SV (several models for settling velocity)

File-Contents (in Catchwords)

Input Steering Data

• global parameters (block Global_Effects)

Selection of some global effects, acting on all active sediment fractions.

• key "Hindered_Settling" : parameter for Hindered Settling:

• selector: perform computation with/without Hindered Settling.
• critical value Cgel: sediment concentration in kg/m**3.

Concerning Hindered Settling: Reduction of settling velocity for high concentrations is due to several interactions between sediment particles. According to Winterwerp Cgel corresponds to a concentration, where a suspension becomes fluid mud. Typical value for Cgel is 80 kg/m**3.

Up to now (January 2018) Hindered_Settling can be combined with every sv model

• key "Flocculation" : parameter for formation and break-up of flocs due to turbulence:

• selector: perform computation with/without flocculation.
• parameter WCA: factor for floc formation..
• parameter WCB: factor for floc break-up.

Concerning Flocculation: Influence of formation as well as break-up of flocs on settling velocity is described through (1+WCA*G)/(1+WCB*G**2). Typical values for WCA and WCB are 0.3 and 0.09. G is the absolute velocity gradient.

Turbulence Flocculation can be combined with the sv models "Constant", "Stokes", "Dietrich", "Power_Law" and "BAW_Approach". Using the models "Manning" or "vanRijn_1993" turbulence flocculation has no influence on the settling velocity.

• key "Power_Law_Exponent" : parameter for nonlinearity of settling velocity in dependence on sediment concentration:

• parameter m: exponent for the power_law and BAW_approach model.

Concerning the power law model: The influence of sediment concentration on settling velocity is given by k*C**m. The faktor k can be prescribed individually for each sediment fraction. A typical value for m is 0.8.

• key "Max_Settling_Velocity" : parameter to avoid high computed settling velocities. value unit is m/s. This parameter is optional. If not using this parameter the value 0.05 m/s will be used internally.

• specific parameters for sediment fractions (block Sediment_Class).

• key "Sediment_Name" : name of sediment class (fraction).
• key "Density" : density of sediment class in kg/m**3.
• key "Diameter" : diameter of sediment class in m.
• key "Model_Type" : settling velocity model:

• Constant: use prescribed constant settling velocity (Constant_SV).
• Stokes: use constant settling velocity according to Stokes.
• Dietrich: use constant settling velocity according to Dietrich.
• Power_Law: compute settling velocity in dependence on sediment concentration (parameter Power_Law_Constant and Power_Law_Exponent) as well as the influence of flocculation (parameter Flocculation).
• Manning: compute settling velocity in dependence on sediment concentration as well as turbulent shear stress according to Manning.
• BAW_Approach: compute settling velocity in dependence on sediment concentration (parameter Power_Law_Exponent) as well as the influence of flocculation (parameter Flocculation). BAW_Approach is a specific Power_Law model. The sediment fraction dependent part of the settling velocity will be computed according to Dietrich.
• vanRijn_1993: compute settling velocity in dependence on sediment concentration according to vanRijn (1993). Need to set parameters in the block vanRijn_1993.

Further informations according to Manning can be found in (ca. 50 kB) Understanding the Sediment Transport Profile.

• (optional) key "Constant_SV" : constant settling velocity in m/s for model Constant.
• (optional) key "Power_Law_Constant" : factor for model Power_Law. Typical value is 0.005.

• specific parameters for vanRijn_1993 model

In this part the fraction independent parameters for vanRijn_1993 will be set

This part is optional. It is necessary to use this part only if the vanRijn_1993 model will be used.

• Key "Flocculation_Constant" : Parameter k [ws = k c**m]
• Key "Flocculation_Exponent" : Parameter m [ws = k c**m]
• Key 'Transition_Concentration' : Limiting concentration cgr in g/l. If c is less or equal to cgr, the flocculation formulation will be used. If c is greater than cgr the hindered settling formulation will be used.
• Key 'HinderedSettling_Constant' : Parameter alpha [ws = ws0 (1 - alpha c)**beta]
• Key 'HinderedSettling_Exponent' : Parameter beta [ws = ws0 (1 - alpha c)**beta]

ws0 in the hindered settling formulation does not have to be specified by the user, because it is assumed that both formulations (flocculation and hindered settling) shall compute the same settling velocity for c equal to cgr. So ws0 can be computed as follows: ws0 = (k * cgr**m) / (1 - alpha * cgr)**beta

General Remarks

1. While reading this steering data file the dictionary file sv_dico.dat will be automatically accessed in directory $PROGHOME/dic/ to support input.

Programs using this Type of File

HSV, UNTRIM2, UNTRIM2007

Example-File

please refer to

$PROGHOME/examples/lib/sv/sv.dat,

$PROGHOME/examples/untrim2007/STD/sv.constant.en.std.dat,

$PROGHOME/examples/untrim2007/STD/sv.dietrich.en.std.dat,

$PROGHOME/examples/untrim2007/STD/sv.stokes.en.std.dat,

$PROGHOME/examples/untrim2007/STD/sv.manning.en.std.dat, as well as

$PROGHOME/examples/untrim2007/STD/sv.power_law.en.std.dat.

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