## What is normal air flow rate in the lungs?

The maximum of the flow rate in the healthy model is approximately 0.059 mm3/s at peak inspiration, while in the NSIP and IPF models, it is approximately 0.032 mm3/s.

## What is Lung viscosity?

Introduction. The viscosity of lung surfactant is dependent on its molecular composition, its microstructure, the interactions between components and the environmental conditions. Viscosity is believed to influence the rate, extent and uniformity of distribution of surfactant in the lungs [1-3].

**What is air flow in the lungs?**

Pulmonary ventilation is commonly referred to as breathing. It is the process of air flowing into the lungs during inspiration (inhalation) and out of the lungs during expiration (exhalation). Air flows because of pressure differences between the atmosphere and the gases inside the lungs.

### What is respiratory fluid?

Respiratory tract fluid, produced from an enormous area spanning the mucosa of the nose to the alveolar surface, is a complex mixture of serum transudate and locally secreted proteins and glycomucoproteins and of inflammatory and immune effector cells intermingled.

### What determines the work of breathing?

Work of breathing is defined as the energy necessary to perform tidal ventilation over a set unit of time. The work of breathing is determined by the pressure-volume characteristics (compliance and resistance) of the respiratory system (Fig. 14.6).

**What is tissue viscous resistance?**

Nonelastic opposition of tissue to ventilation due to the energy required to displace the thorax and airways.

#### What causes turbulent air flow in lungs?

Turbulent flow refers to when air is not flowing in parallel layers, and direction, velocity and pressure within the flow of air become chaotic. If airflow becomes turbulent, the pressure difference required to maintain airflow will need to be increased, which in turn would increase turbulence and therefore resistance.

#### How can I increase airflow in my lungs?

To practice the pursed-lips breathing technique:

- Inhale slowly through your nostrils.
- Purse your lips, as if pouting or about to blow on something.
- Breathe out as slowly as possible through pursed lips. This should take at least twice as long as it did to breathe in.
- Repeat.

**How long can I live with pleural effusion?**

Malignant pleural effusion (MPE) is a common but serious condition that is related with poor quality of life, morbidity and mortality. Its incidence and associated healthcare costs are rising and its management remains palliative, with median survival ranging from 3 to 12 months.

## What is the stress tensor in fluid mechanics?

A key step in formulating the equations of motion for a fluid requires specifying the stress tensor in terms of the properties of the flow, in particular the velocity field, so that the theory becomes “closed”, that is, that the number of variables is reduced to the number of governing equations.

## What is the rate-of-strain tensor?

The symmetric term E of velocity gradient (the rate-of-strain tensor) can be broken down further as the sum of a scalar times the unit tensor, that represents a gradual isotropic expansion or contraction; and a traceless symmetric tensor which represents a gradual shearing deformation, with no change in volume:

**What is the second invariant of the viscous stress tensor?**

The second invariant of the viscous stress tensor is IIT≡ 1 2. h. τijτij−(τkk) 2. i. (1.6.14) = τ2 12+τ. 2 23+τ31 −(τ11τ22+τ11τ33+τ22τ33) Similarly the second invariant of the rate of strain tensor is IIE≡ 1 2. h.

### What is the actual strain rate in a rigid rotation?

A rigid rotation does not change the relative positions of the fluid elements, so the antisymmetric term R of the velocity gradient does not contribute to the rate of change of the deformation. The actual strain rate is therefore described by the symmetric E term, which is the strain rate tensor .