Search the Community

Hi folks, please find attached a fully parametric and CFD-ready twisted spade rudder geometry, optional with costa bulb. This design offers you to use your own profile definition for each part of the rudder - the blade, the skeg and the costa bulb. Therefore the respective auxiliary scope consists of a feature which allows you to load a point-data file from your hard disk. In order to provide you a working setup I detached the imported NACA0018 profile (you can find the profile as a NURBS curve "imported_profile" in each auxiliary scope). If you want to use your own profile, simply load the data file and set it as input for the curve engines, respectively the image-profile for the costa bulb. A few requirements have to be considered: The imported profile has to have its leading edge at x=0 and its trailing edge at x=1. Moreover the z-coordinate should be =0 for all points, the profile has to have an open trailing edge and the profile has to be a full profile (e.g. starting at the suction side trailing edge and ending at the pressure side trailing edge). A fully implemented delta shift function twists the imported profile in a way, that the forward part of the profile is shifted in y-direction defined by a twist angle. Furthermore the start of the shift in x-direction, "twist start", as well as the intensity, "twist weight", of the shift can be controlled. The twist angle will twist the lower rudder part half the angle in one direction and upper rudder part half the angle in the other direction. The rudder blade, and the skeg are modeled using metasurfaces, thus the geometry is described by functions, which can be customized as well. The rudder blade is defined by a few typical parameters, such as blade area (= shadow area), blade height, profile chord length at the upper edge and the length of the profile from the rudder shaft to the leading edge at the top and the bottom. In addition you can define the propeller shaft height, the twist angle and the twist transition length, meaning the twist transition between lower and upper blade part in % of the blade length. For a reasonable surface this value should not be smaller than 0.2. All parameters can be found in the parameters scope, sorted by the rudder parts. Finally all surfaces are meshed and joined in a CFD-ready STL. If you want to get rid of the costa bulb simply remove the object from the boolean sum: 03_STL -> twisted_rudderSTL. The idea is, that the rudder STL intersects with a hull STL so that both can be joined in a final STL. Therefore you have to make sure, that the upper part of the rudder skeg lays within the hull overhang. If you have questions, do not hesitate to post them! Cheers Matthias twistedRudder_costaBulb.fdb

Hi folks, please find attached a fully parametric model of a WED - Wake Equalizing Duct. Such a device can increase the wake homogeneity and the hull propeller efficiency. In the project (baseline > abdy > appendages > duct) you can find three sets of parameters (in the scope 04Parameters): The first set controls the path of the duct which consists of three parts, an upper flat, an round mid-part and an lower flat. The parameters for the path are shown in the figure below. The second set of parameters controls the section of the duct. The standard parameters for a NACA 4 digit profile (chord length, maximum thickness, camber and camber position) are kept constant but can easily be replaced by functions. The angle of attack can be varied for three positions (shown in the figure below). The third set of parameters controls the global position of the duct. With xpos and zPos you can move the duct to the destination. With totalScale you can scale the duct. Taking into account the direction of the skeg surface (the red line shown in the figure below is a surface curve on the skeg at the height of the center of the duct) the duct aligns to the surface and to the surrounding flow. With the parameter addFlowAnlge you can apply an additional angle which results in a rotation around the z-Axis. The parameter AOATotal effects a rotation around the y-Axis. For external CFD computations you can find a watertight trimesh (imDuctMesh) and the parameter openEdges which checks the watertightness. This parameter can be used as a constraint for the computation. Cheers Matthias WED.fdb

Hi All, Please try out this parametric CAESES model of a volute for a blower. The basic shape is controlled by a function (red) to control the offset of the outer shape from the inner circle. If you switch off the visibility of the trimesh (named volute, click on its icon in the object tree) you can see the surface topology behind it. If you are a bit experienced, such a model is set up in 15 min from scratch. Have fun!volute1.fdb