Method and computer readable media for determining orientation of fibers in a fluid

A computer-implemented method for determining orientation of fibers in a fluid having polymer chains, comprising a step of calculating using a computer processor the orientation of the fibers by taking into consideration an interaction between the fibers and the fluid, wherein the interaction between the fibers and the fluid comprises changes in configuration of the polymer chain to cause the entanglement or adsorption between the fibers and the polymer chains;

• wherein the interaction is represented using an expression:
• {dot over (A)}RPR=−R·{dot over (Λ)}IOK·Rt;
• wherein {dot over (A)}RPR represents the interaction;
• R represents a rotation matrix;
• Rt represents a transpose matrix of the rotation matrix R;
• Λ represents a diagonal tensor of a orientation tensor of fibers A;
• {dot over (Λ)}IOK represents a rate of the diagonal tensor with respect to time;
• e1, e2, and e3 represent eigenvectors of the orientation tensor A;
• and the rotation matrix R is given by the eigenvectors, R=[e1,e2,e3].

A computer-implemented method for determining orientation of fibers in a fluid having polymer chains, the fibers in the fluid including a transitional movement and a rotatary movement, the method comprising a step of calculating using a computer processor the orientation of the fibers by taking into consideration a steric barrier effect on a rotary movement of the fibers;

• wherein the steric barrier effect on the rotary movement of the fibers is represented using an expression:
• D
• r
• =
• f
• ⁡
• (
• L
• ~
• )
• ;
• L
• ~
• =
• L
• T
• ·
• L
• L
• T
• :
• L
• ;
• wherein Dr represents an anisotropic rotary diffusion tensor;
• {tilde over (L)} represents a second order symmetric tensor with its trace({tilde over (L)})=1;
• L represents a velocity gradient tensor;
• ƒ({tilde over (L)}) represents a function of the tensor {tilde over (L)};
• and LT represents a transpose matrix of the velocity gradient tensor L.

A computer-implemented method for determining orientation of fibers in a fluid having polymer chains, the fibers in the fluid including a transitional movement and a rotatary movement, the method comprising a step of calculating using a computer processor the orientation of the fibers by taking into consideration a steric barrier effect on a rotary movement of the fibers;

• wherein the steric barrier effect on the rotary movement of the fibers is represented using an expression:
• D
• r
• =
• D
• 0
• ⁡
• (
• I
• -
• C
• M
• ⁢
• L
• ~
• )
• ;
• L
• ~
• =
• L
• T
• ·
• L
• L
• T
• :
• L
• ;
• wherein Dr represents an anisotropic rotary diffusion tensor;
• D0 represents a rotary diffusion parameter indicative of fiber-fiber interactions;
• CM represents a steric mobile barrier parameter of the fiber embedded in the fluid;
• I represents an identity matrix;
• {tilde over (L)} represents a second order symmetric tensor with its trace({tilde over (L)})=1;
• L represents a velocity gradient tensor;
• and LT represents a transpose matrix of the velocity gradient tensor L.

A non-transitory computer medium containing computer instructions stored therein for causing a computer processor to perform operations for determining orientation of fibers in a fluid having polymer chains, the operations comprising a step of calculating the orientation of the fibers by taking into consideration an interaction between the fibers and the fluid, wherein the interaction between the fibers and the fluid comprises changes in configuration of the polymer chain to cause the entanglement or adsorption between the fibers and the polymer chains;

• wherein the interaction is represented using an expression:
• (
• ⅆ
• ψ
• ⅆ
• t
• )
• IOK
• =
• -
• k
• ⁢
• ⁢
• ψ
• ;
• k
• =
• (
• pp
• )
• -
• 1
• ⁢
• :
• ⁢
• (
• ⅆ
• pp
• ⅆ
• t
• )
• IOK
• ;
• wherein ψ represents a probability density function of aligned fibers;
• [
• ⅆ
• ψ
• ⅆ
• t
• ]
• IOK
• represents a change in the probability density function of the aligned fibers decaying with respect to time;
• k represents a characteristic constant of the interaction between the fibers and the fluid;
• pp represents orientation tensor of a fiber;
• (pp)−1 represents inverse of orientation tensor pp;
• and
• [
• ⅆ
• pp
• ⅆ
• t
• ]
• IOK
• represents a change in orientation tensor pp with respect to time.

A non-transitory computer medium containing computer instructions stored therein for causing a computer processor to perform operations for determining orientation of fibers in a fluid having polymer chains, the operations comprising a step of calculating the orientation of the fibers by taking into consideration an interaction between the fibers and the fluid, wherein the interaction between the fibers and the fluid comprises changes in configuration of the polymer chain to cause the entanglement or adsorption between the fibers and the polymer chains;

• wherein the interaction is represented using an expression:
• {dot over (A)}RPR=−R·{dot over (Λ)}IOK·Rt;
• wherein {dot over (A)}RPR represents the interaction;
• R represents a rotation matrix;
• Rt represents a transpose matrix of the rotation matrix R;
• Λ represents a diagonal tensor of a orientation tensor of fibers A;
• {dot over (Λ)}IOK represents a rate of the diagonal tensor with respect to time;
• e1, e2, and e3 represent eigenvectors of the orientation tensor A;
• and the rotation matrix R is given by the eigenvectors, R=[e1,e2,e3].

A non-transitory computer medium containing computer instructions stored therein for causing a computer processor to perform operations for determining orientation of fibers in a fluid having polymer chains, the fibers in the fluid including a transitional movement and a rotatary movement, the operations comprising a step of calculating the orientation of the fibers is performed by taking into consideration a steric barrier effect on a rotary movement of the fibers;

• wherein the steric barrier effect on the rotary movement of the fibers is represented using an expression:
• D
• r
• =
• f
• ⁡
• (
• L
• ~
• )
• ;
• L
• ~
• =
• L
• T
• ·
• L
• L
• T
• :
• L
• ;
• wherein Dr represents an anisotropic rotary diffusion tensor;
• {tilde over (L)} represents a second order symmetric tensor with its trace({tilde over (L)})=1;
• L represents a velocity gradient tensor;
• ƒ({tilde over (L)}) represents a function of the tensor {tilde over (L)};
• and LT represents a transpose matrix of the velocity gradient tensor L.

A non-transitory computer medium containing computer instructions stored therein for causing a computer processor to perform operations for determining orientation of fibers in a fluid having polymer chains, the fibers in the fluid including a transitional movement and a rotatary movement, the operations comprising a step of calculating the orientation of the fibers is performed by taking into consideration a steric barrier effect on a rotary movement of the fibers;

• wherein the steric barrier effect on the rotary movement of the fibers is represented using an expression:
• D
• r
• =
• D
• 0
• ⁡
• (
• I
• -
• C
• M
• ⁢
• L
• ~
• )
• ;
• L
• ~
• =
• L
• T
• ·
• L
• L
• T
• :
• L
• ;
• wherein Dr represents an anisotropic rotary diffusion tensor;
• D0 represents a rotary diffusion parameter indicative of fiber-fiber interactions;
• CM represents a steric mobile barrier parameter of the fiber embedded in the fluid;
• I represents an identity matrix;
• {tilde over (L)} represents a second order symmetric tensor with its trace({tilde over (L)})=1;
• L represents a velocity gradient tensor;
• and LT represents a transpose matrix of the velocity gradient tensor L.