FLIQUID_ConsistentPressure_Version

Default: FLIQUID_ConsistentPressure_Version = 1327

option	description
first digit	Version of how to compute the consistent dynamic pressure, cf. DynamicPressureAlgorithm.
	Version 1: div((1/rho)*grad_p) = ... see ClassicalDPA
	Version 2: sum( W_ij*(p_j-p_i) ) = ... see AlternativeDPA
	Version 3: experimental, do not use.
	Version 4: dynamic pressure is not computed (i.e. it remains what is there from the step \( p_{dyn}^{n+1} = p_{dyn}^n + c\) with \( c\) denoting the correction pressure in the Chorin (v--) or penalty (vp-) formulation
second digit	Version how to reconstruct the Lagrangian acceleration.
	see reconstructLagrangianAcceleration
third digit	Version how to compute PSI, see ComputationOfPSI.
	Version 1: div(div(eta*grad(v)))
	Version 2: divBAR(div(eta*grad(v)))
fourth digit	Version how to compute PHI.
	There are 8 variations, see ComputationOfPHI. This option makes sense only in case of the ClassicalDPA. In case of AlternativeDPA, keep this value at 1.
fifth digit	optional. If reconstructLagrangianAcceleration is set to 1 or 3 or 4, the user assumes a quasistatic flow field. Quasistatic flow field might be given only under a certain refence velocity \( \mathbf{v}_{ref}\).
	see referenceVelocity
	Version 0: (default): reference velocity is ZERO.
	Version 1: reference velocity is equal to the mean boundary velocity

Note: The second digit has impact only if

• regularization of the pressure system is requested by RegularizeDPA. Here, it impacts the way the target pressure gradient is computed.
• version 4 or 8 is used for ComputationOfPHI (fourth digit).
• %BND_none% is used as a boundary condition, as this condition is based on the AlternativeDPA-algorithm, and so this digit impacts the computation of the target pressure gradient.

We recommend: or

useful options	characteristics of the numerical results
FLIQUID_ConsistentPressure_Version = 1111 (classical approach)	%BND_none% only valid in quasistationary boundaries
FLIQUID_ConsistentPressure_Version = 1127 (same as 2111)	very smooth results, also here %BND_none% only valid in quasistationary boundaries
FLIQUID_ConsistentPressure_Version = 1227	%BND_none% valid in any case, as accelerations are computed exactly. However, the results might be noisy.
FLIQUID_ConsistentPressure_Version = 1327	%BND_none% valid in any case. However, accelerations are computed on a local quasistationary approach (each point forms an observer coordinate system). These values might be less precise than 1227, the results however are more smooth.
FLIQUID_ConsistentPressure_Version = 1228	Numerically most natural, as the acceleration is given by the finite temporal difference of the previous and current velocities, and PHI is the divergence of this term. However, it produces more noises in the pressure solution.

Note: The understanding of "quasistationary" is:

• at a fixed location of an observer, the physical quantities only slowly change in time.
• watercrossing with fixed pool and moving car IS NOT quasistationary, because an observer standing in the pool will notice dramatic changes as the car drives by.
• watercrossing with fixed car and moving pool IS INDEED quasistationary, because the observer in the car will see slow changes of the water motion as the car constanty drives through the pool.

In case of non-quasistationary flow, set FLIQUID_ConsistentPressure_Version = 1227 or FLIQUID_ConsistentPressure_Version = 1327.