.cmode.csv file

This file is an output file generated during an Acoustic Complex Eigenvalue Analysis.

File Creation

This file is created when the PARAM, FCACSV Bulk Data Entry is set to -1 or 2 in an Acoustic Complex Eigenvalue Analysis.

File Contents

This file consists of four sections including Mass Fraction, Modal Assurance Criterion (MAC) – Structural, Modal Assurance Criterion (MAC) – Interface (Wet Surface), and Modal Assurance Criterion (MAC) – Fluid.

Mass Fraction

File Format

Column: Description
Mode ID: Complex mode ID
Eigenvalue(R): Real part of eigenvalue
Eigenvalue(I): Imaginary part of eigenvalue
Frequency: Frequency of modes
Mass Fraction(S): Mass fraction (structural)
Mass Fraction(F): Mass fraction (fluid)

Modal Assurance Criterion (MAC) – Structural

File Contents

Mapped Structural Modes:

A complex coupled mode corresponding to only structural grids is correlated with each uncoupled structural mode. The mode with the highest MAC value is chosen for printing under Mapped Mode ID shown in Figure 2. Corresponding frequency difference values are then calculated. There is an extra column, MAC_Wet(S), which contains MAC values of the coupled mode corresponding to wet structural grids versus uncoupled structural mode (this mode is already identified via mapped mode ID).

Coupled Mode ID: ID of full eigenvector coupled mode (For example, mode Α₁).
Mapped Mode ID(S): ID of full eigenvector (EV) uncoupled structural mode.; This mode is identified as the uncoupled mode with the highest MAC(S).
MAC(S): MAC values are calculated for: Coupled mode (Α₁) EV corresponding to the only structural grids versus each full EV uncoupled structural mode (mode 1 to mode N, where N is the total number of uncoupled structural modes).; The highest such obtained MAC value is printed as MAC(S) and the corresponding uncoupled structural mode ID is printed as “Mapped Mode ID(S)".
MAC_Wet(S): MAC value is calculated for: Coupled mode (Α₁) EV corresponding to only the wet surface structural grids versus uncoupled structural mode (identified in the Mapped Mode ID(S) field) corresponding to the wet surface structural grids.

File Format

Column: Description
Mapped Mode ID: Mapped uncoupled structural mode ID
Frequency: Frequency of uncoupled structural mode
Frequency Diff(S): Frequency Diff: Coupled mode – Uncoupled mode
Frequency Diff(S) (%): Percentage of frequency difference
MAC(S): Modal Assurance Criterion: Coupled modes (structural grids only) versus uncoupled full eigenvector structural modes (MAC)
MAC_Wet(S): Model assurance criterion values for coupled modes versus structural wetted modes
Important: These are modes of the wet surface structural grids for corresponding modes in the listed Mapped Mode ID(S) column.

Modal Assurance Criterion (MAC) –Interface (Wet Surface)

File Contents

Mapped Wetted Modes:

A coupled mode corresponding only to structural grids of the wet surface is correlated with each uncoupled structural mode corresponding to the structural grids of the wet surface. The one with highest MAC value is chosen for printing under Mapped Mode ID shown in Figure 3. Corresponding frequency difference values are then calculated.

Coupled Mode ID: ID of full eigenvector coupled mode (For example, mode Α₁).
Mapped Mode ID(WS): ID of uncoupled structural mode corresponding only to structural grids of the wet surface.; This mode is identified as the corresponding uncoupled structural mode with the highest MAC(WS).
MAC(WS): MAC values are calculated for: Coupled mode (Α₁) corresponding only to structural grids of the wet surface versus each uncoupled structural mode corresponding only to structural grids of the wet surface (mode 1 to mode N, where N is the total number of uncoupled structural modes).; The highest such obtained MAC value is printed as MAC(WS) and the corresponding uncoupled structural mode ID is printed as “Mapped Mode ID(WS)".

File Format

Column: Description
Mapped Mode ID(WS): Mapped uncoupled mode ID corresponding to the wet surface
Frequency(WS): Frequency of mode ID corresponding to the wet surface
Frequency Diff(WS): Frequency Diff: Coupled mode corresponding to the wet surface – Uncoupled mode corresponding to the wet surface
Frequency Diff(WS) (%): Percentage of frequency difference
MAC(WS): Model assurance criterion values for uncoupled modes corresponding to wet surface versus coupled modes corresponding to the wetted surface

Modal Assurance Criterion (MAC) – Fluid

File Contents

Mapping Fluid Modes:

A coupled mode corresponding to only the fluid grids is correlated with each uncoupled fluid mode and the one with highest MAC value is chosen for printing under Mapped Mode ID, as shown in Figure 4. Corresponding frequency difference values are then calculated.

Coupled Mode ID: ID of full eigenvector coupled mode (For example, mode Α₁).
Mapped Mode ID: ID of full eigenvector (EV) uncoupled fluid mode.; This mode is identified as the uncoupled mode with the highest MAC(WS).
MAC(F): MAC values are calculated for: Coupled mode (Α₁) EV corresponding to only the fluid grids versus each full EV uncoupled fluid mode (mode 1 to mode N, where N is the total number of uncoupled fluid modes).; The highest such obtained MAC value is printed as MAC(F) and the corresponding uncoupled structural mode ID is printed as “Mapped Mode ID(F)".

File Format

Column: Description
Mapped Mode ID(F): Mapped uncoupled fluid mode ID
Frequency: Frequency of uncoupled fluid mode
Frequency Diff(F): Frequency Diff: Coupled mode – Uncoupled mode
Frequency Diff(F) (%): Percentage of frequency difference
MAC(F): Model assurance criterion values for fluid modes versus coupled modes