public void setSurfaceTangentFactor(float surfaceTangentFactor) {
        this.surfaceTangentFactor = surfaceTangentFactor;
    }
This method sets the surface tangent factor.
@param surfaceTangentFactor
       the surface tangent factor
jme3-core/src/main/java/com/jme3/effect/influencers/NewtonianParticleInfluencer.java