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CORMIX Classification System

CORMIX contains a rigorous flow classification scheme developed to classify a given discharge/environment interaction and mixing behvior into one of several flow classes with distinct hydrodynamic features.

The classification scheme places major emphasis on the near-field behavior of the discharge and uses the length scale concept as a measure of the influence of each potential mixing process.

Flow behavior in the far-field, after boundary interactions, is largely controlled by ambient conditions.

Once a flow has been classified, integral, length scale, and passive diffusion simulation modeling methods are utilitzed to predict the flow process details.

Rule Base Example

Figure on the right illustrates a rule from the Flow Classification Rule Base for determination of CORMIX flow class V2.

A rule base contains a collection of IF(conditions)-THEN(conclusions) logic statements (or rules), where statements contained within the IF clause are conditions, while statements within the THEN clause are conclusions or hypotheses. B in the figure above shows that one rule's conditions may themselves be conclusions of other rules as shown in these rule-tree diagrams.

The system uses both backward (deductive logic) and forward chaining (inductive logic) strategies to reach conclusions about mixing zone flow behavior, regulatory compliance, and design optimization.

The classification scheme is implemented within CORMIX using Artificial Intelligence (AI) techniques of rule-based expert systems.

These techniques are used to assist in technology tranfer and to give the analyst flexible and powerful tools for mixing zone analysis.

CORMIX rule bases check for input data consistency, calculate basic length scales and flow parameters, determine the flow class, and create the output reports with simulation model details of mixing zone behavior and regulatory compliance. The rule bases also relay conclusions about mixing zone processes to the analyst.

In addition, the classification scheme and rule-base forms a basis for methodical examination of initial mixing properties for environmental impact assessment, regulatory compliance evaluation, ecological impact mitigation and outfall design. Finally, the rule base provides a foundation for outfall design optimization strategies.

CORMIX1 V Flow Classification.
CORMIX1 Classification: Behavior of positively buoyant discharges in uniform ambient layer (larger image), Doneker and Jirka, EPA 600/3-90/-012.


CORMIX Rule Tree Example.
An example of one IF-THEN rule from the flow classification rule base (larger image).


S3 rule decision tree example.
A rule-tree illustration of the rules fired by the inference engine for flow classification (larger image).
CORMIX1- Classification Scheme: Single Port Discharges
CORMIX1 Stratified S flow classes.
CORMIX1 Classification: Assessment of ambient density stratification and different flow classes for internally trapped flows (larger image).
CORMIX1 V Flow Classes.
CORMIX1 Classification: Behavior of positively buoyant discharges in uniform ambient layer (larger image).
CORMIX1 NV and NH Flow Classes.
CORMIX1 Classification: Behavior of negatively buoyant discharges in uniform layer flow (Flow Classes NV and NH) (larger image).
CORMIX1 Attached Flow Classes
CORMIX1 Classification: Dynamic bottom attachment of discharge due to wake or Coanda effects (larger image).
CORMIX2- Classification Scheme: Multiport Diffuser Discharges
CORMIX2 MS Stratified Flow Classes.
CORMIX2 Classification: Assessment of ambient density stratification and different flow classes for internally trapped flows (larger image).
CORMIX2 MU Flow Classes
CORMIX2 Classification: Behavior of positively buoyant multiport diffuser discharges in uniform ambient layer (larger image).
CORMIX2 MN Flow Clases.
CORMIX2 Classification: Behavior of negatively buoyant multiport diffuser discharges in uniform ambient layer (larger image).
CORMIX3- Classification Scheme: Positively Buoyant Surface Discharges
CORMIX3 Surface Discharge Flow Classes.
CORMIX3 Classification: Assessment of buoyant surface discharges as free jets, shoreline-attached jets, wall jets (larger image).