Linear wind
The Linear wind can be selected in the Atmosphere part. A linear wind is defined by the following parameters:
- Start speed $$V_0$$
- End speed $$V_e$$
- Start-up duration $$T_0$$
- Duration $$T$$
The role of these parameters is illustrated in the following figure:
The magnitude of the wind speed at the hub
$$V_{hub}$$
is defined as follows:$$V_{hub}=\left\{\begin{array}{lll} V_0&\text{for}&t{<}T_0\\V_0+ (t-T_0)\cdot\frac{V_e-V_0}{T}&\text{for}&T_0\leq t {<} T_e\\ V_e&\text{for}&t\geq T_e\\ \end{array}\right.$$
The same equation applied for the Wind angle
$$\alpha$$
, replacing the start speed $$V_0$$
and the end speed $$V_e$$
with the start angle $$\alpha_0$$
and the end angle $$\alpha_e$$
, respectively:$$\alpha=\left\{\begin{array}{lll} \alpha_0&\text{for}&t{<}T_0\\\alpha_0+ (t-T_0)\cdot\frac{\alpha_e-\alpha_0}{T}&\text{for}&T_0\leq t {<} T_e\\ \alpha_e&\text{for}&t\geq T_e\\ \end{array}\right.$$