Three different types of time constant currents may be defined in QBlade. An overview of the available types of currents is given below. Further details can be found in Energy1.

  • Near-Surface Currents: The velocity profile of a near-surface current varies linearly with depth from a specified velocity at the sea surface to zero at the reference depth, which is defined by the user.

  • Sub-Surface Currents: The sub-surface current velocity follows a power law profile. The implementation in QBlade is of the following form:

\[\begin{align} u_{cs}(z) = \left[\left(\frac{z+h}{h}\right)^\alpha \right]u_{s0}(z=0) \end{align}\]


  • \(u_{cs}(z=0)\) is the velocity at the sea surface,

  • \(\alpha\) is the power law exponent (deault value is \(\alpha = 0.14\)),

  • \(h\) is the water depth,

  • \(z\) is \(0 \geq z \geq-h\).

  • Near-Shore Currents: The near-shore current is defined as a uniform velocity profile independent of the depth

Any combination of these types of currents (together with waves) may be included within a QBlade simulation. In all cases, the velocities at each evaluation point are calculated as a superposition of all contributions from waves and currents. A complete hydroelastic representation of the turbine also requires the consideration of fluid-structure interaction. This topic is covered in Sections Linear Potential Flow Theory and Morison Equation.


DNV GL - Energy. Theory Manual Bladed. 2014. [Version 4.6].